- Barcelona is the latest major European city to face a deadly terror attack claimed by the "Islamic State" (IS) armed group. Thirteen people were killed and more than 100 injured on Thursday afternoon when a van plowed into crowds on a busy tourist street.

Eyewitnesses described their horror as they saw a vehicle zigzagging through Las Ramblas, near Plaza Catalunya, with the apparent goal of running over as many people as possible.

Later one suspect was shot dead by police and two others were detained. But police say none of them was the driver. The alleged attacker remained at large on Friday morning having escaped from the atrocity on foot.

- Less than 12 hours later, another dramatic incident unfolded about 120 kilometers (75 miles) south of Barcelona when police killed four suspected attackers who they believe were about to carry out a separate attack in the nearby seaside town of Cambrils. Seven civilians and a police officer were injured during that incident, early on Friday morning.

- The dramatic events took a further twist when police revealed both incidents were linked to an explosion at a house on Wednesday in a third Catalan town, which left at least one person dead.

Read a summary of the events here.

Live updates - all times are UTC

03:16 Fifteen people - out of more than 100 injured - remain in a critical condition following Thursday's attack in Barcelona, officials say. Two of the seven hurt in the Cambrils attack were also seriously injured.

03:01 Catalan police have confirmed earlier Spanish news reports that the five suspects killed in the holiday resort town of Cambrils early on Friday were carrying bomb belts and had run over civilians with their car.

02:28 The spire of New York's One World Trade Center has been lit up in the colors of the Spanish flag in solidarity with Barcelona following Thursday's deadly terror attack.

02:24 El Mundo newspaper has cited a Catalan government spokesman as saying that police believe the terror suspects were driving round the town of Cambrils in an Audi A3 before they were shot dead. Spanish media reports that the attackers had plowed the vehicle into several pedestrians in a similar incident to the Barcelona assault.

02:17 The fifth suspect shot during an apparent terrorist attack in Cambrils has died, Catalonia police say. The suspect was injured when police launched an operation to foil Spain's attack in less than 12 hours.

01:26 Police in Cambrils say they are planning to carry out controlled explosions following a second suspected terror incident hours after the Barcelona van attack. They have urged local residents not be alarmed.

01:18 The terror suspects killed in Cambrils early on Friday are likely linked to the Barcelona attack and the explosion in Alcanar, police say. Six civilians and a police officer were injured in the second attack. Earlier police confirmed four suspected attackers were killed and another wounded.

01:10 Police in Cambrils - 120 kilometers (75 miles) southwest of Barcelona - say their operation is ongoing but for now is under control. They've warned the public to remain indoors for the next few hours following what they say was an attempted second terror attack in Spain's autonomous region of Catalonia.

00:43 The four suspects shot and killed in a town south of Barcelona early on Friday may have been carrying suicide explosive belts, Spain's public broadcaster RTVE says. Seven people were injured in the latest incident, two seriously, according to the broadcaster.

Police say a fifth suspect was injured and taken into custody.

The shootout took place just after 1 a.m. local time (23:00 UTC) on the promenade in the town of Cambrils, about an hour southwest of Barcelona, Spanish media reported. The police operation took place less than 12 hours after the van rampage in Barcelona that left 13 people dead and more than a hundred injured.

00:02 Police sources have told El Mundo newspaper that those killed were attempting to replicate in Cambrils an attack similar to the deadly rampage in Barcelona.

A Catalan police spokeswoman has confirmed that four alleged perpetrators have been killed and one was injured.

The newspaper La Vanguardia says a shootout took place on the town's harbor side early on Friday.

23:58 Several attackers have been killed in a shootout in Cambrils, south of Barcelona, according to Spanish media. The news channel 24 Horas says four people have died and one other injured.

23:44 Police say they're responding to a "possible terrorist attack" in Cambrils, an hour's drive south of Barcelona, after launching an operation. It comes amid an ongoing manhunt for the perpetrator of Thursday's deadly van attack in Barcelona. The coastal town is popular with Spanish tourists.

La Vangardia newspaper has cited several eyewitnesses who say they've heard shots ringing out in the town.

23:25 Catalan authorities say a police operation is underway in Cambrils, a town 21 kilometers (13 miles) southwest of Tarragona, without giving further details. They've warned local residents to remain indoors.

23:16 Residents of a house in Alcanar some 100 kilometers (62 miles) south of Barcelona - where a blast detonated a day before Thursday's attack -  were preparing explosives, a Catalan police source tells the Reuters news agency. At least one person was killed in the explosion, which police initially thought was an accident. Authorities are now linking the two incidents.

23:06 Catalan authorities say at least 18 nationalities are among the Barcelona attack victims. Nationals of France, Germany, Spain, the Netherlands, Argentina, Venezuela, Belgium, Australia, Hungary, Peru, Romania, Ireland, Greece, Cuba, Macedonia, China, Italy and Algeria were caught up in the atrocity, according to a Catalan government spokesman.

23:00 As news spread about the attack, footballers from FC Barcelona and other Spanish teams have taken to social media to express their horror and send condolences to the victims. They include Barca striker Lionel Messi.

In an Instagram post, he said "We are not going to give up, there are many more of us who want to live in a world of peace, without hate and where respect and tolerance are the basis of coexistence."

Real Madrid's Cristiano Ronaldo also tweeted, offering his full support and solidarity with the families and friends of the victims.

22:45 New York's One World Trade Center, the main tower of the rebuilt World Trade Center complex, will be illuminated in the Spanish flag on Thursday night in honor of those killed in the Barcelona attack.

22:28 Spain's Prime Minister Mariano Rajoy has told a news conference that the Barcelona atrocity was a "jihadist attack."

"We are united in our mourning and in our determination to overcome those who want to rob us of our values and our way of life," he said, after traveling to the northeast city on Thursday evening.

Rajoy insisted that terrorism can be beaten and that it is a worldwide problem that must be tackled globally.

He promised the "full support" of the central government to Catalan officials in their response to the attack.

22:12 Catalan police have urged the public not to share images of Thursday's attack on social media. They also requested that residents don't upload photos or videos detailing any counter-terrorism operations in the city, without giving further details.

21:49 Spain's Prime Minister Mariano Rajoy has traveled to Barcelona to be briefed on the attack by regional officials. He is due to give a press conference later this evening, according to local media.

21:45 Spanish media are reporting that Las Ramblas, where the attack took place, has tonight been partially reopened to the public.

21:39 Police have confirmed the driver of the van that plowed into shoppers and tourists in a Barcelona street earlier remains on the run on Thursday night.

21:35 Trapero has revealed the nationalities of the two suspects detained following Thursday's atrocity. One is Moroccan and the other is a Spanish national from Melilla, a Spanish enclave on Africa's north coast that neighbors Morocco.

21:31 During the latest press conference, regional police chief Trapero has attempted to reassure residents and tourists that authorities don't believe another terror attack in Barcelona is imminent, based on intelligence.

21:26 The interior chief of Spain's Catalan region Joaquim Forn says three days of mourning have been declared and a minute's silence will be held for the victims on Friday. Barcelona Mayor Ada Colau tweeted that the ceremony would be held at 12pm local time (10:00 UTC).

21:17 Read more: Barcelona terror attack: Leaders mourn victims

21:12 Trapero says the person killed had no relation to the attack. He says neither of the two people arrested was the driver in the attack. One of men was arrested in Alcanar and the other in Ripoll.

21:10 Trapero says that an explosion the night before in Alcanar, a town 160 kilometers (100 miles) south west of Barcelona, was related to today's attack. That explosion killed one person and wounded seven others as well as leveling a house. Authorities initially thought the explosion was accidental but now believe it was "connected" to the Barcelona attack.

21:07 The head of the Catalan police Josep Lluis Trapero has given the official version of events at a press conference. He said that at 16.50 local time a van entered the pedestrian mall of Las Rambla at high speed traveling 500 meters (1,650 feet), hitting more than 100 people and killing 13 of them. When the van reached Liceu Theater the attacker fled. Witnesses provided police with a description of the driver and counterterrorism measures were activated. There is no evidence that the driver was armed.

20:58 The Interior Ministry has confirmed that one suspect has died.

20:55 Police are saying more than 100 people have been injured and 13 people have died. They say that figure could climb in the coming hours.

20:54 The mayor of the home town of one of the suspects has confirmed accounts that the man was apprehended as he tried to claim his innocence. The Moroccan-born 28-year-old was intercepted on his way to the police station after he saw his photo and his name in the media, the mayor of Ripoll, Jordi Munuell, told various Spanish outlets. 

Catalan outlets report that police are now operating on the hypothesis that the man's brother had stolen his passport and then taken part in the attack. Police have confirmed that two men have been arrested.

20:44 United Nations Secretary General Antonio Guterres has condemned the attack in a statement released by the UN.

"He extends his heartfelt condolences to the families and friends of those killed and to the Government and people of Spain.  He wishes a speedy recovery to those injured and hopes that those responsible for this heinous violence will be swiftly brought to justice," the statement says.

20:31 Emergency services say 13 people were killed, 15 people were seriously injured, 23 had less serious injuries, and 42 people had mild injuries. They were taken to various hospitals around the city.

20:22 The Mayor of Paris has said that the French capital will extinguish the lights on the Eiffel Tower tonight in tribute to the victims of the attack.

20:13 The Belgian Foreign Ministry has confirmed that one of its citizens was killed in the attack. 

20:07 The Telegram account of the so-called Islamic State's news outlet Amaq has sent out a message saying: "The executors of the Barcelona attack were soldiers of the Islamic State," although it did not name the people it claimed were behind the attack. It said they launched the attack as part of a call to target nations that are taking part in the US-led coalition battling the jihadist group in Iraq and Syria.

19:51 Details are emerging of one of the arrested suspects. The man who is accused of renting the truck was reportedly known to police for previous convictions, for which he was jailed. Spanish media have reported the man was born in Morocco in 1989 and was a resident of Spain. He had also lived in Marseille, France, according to local outlets. It was unclear whether this was the man who presented himself to police to say his passport had been misappropriated by the attackers.

19:44 Read more: Madrid to Manchester to London: A chronology of terror in Europe

19:41 A person whose passport was found in the rented truck has reportedly presented himself to police, saying his identity was stolen, La Vanguardia reports.

19:24 The so-called Islamic State has claimed responsibility for the attack through its online new agency. 

19:18 The Islamic Commission of Spain expressed its "most emphatic condemnation of and repulsion to the terrorist attack" in a statement.

"The Islamic Commission reiterates its full commitment to the fight against all forms of terrorism, and it hopes that those responsible for these attacks can be detained and brought to justice as soon as possible."

19:14 President of the Generalitat of Catalonia Carles Puigdemont continues to say that two people have been arrested. "Catalonia will rise to the occasion to defend peace and freedom. Democracy will break barbarism," he says.

19:12 The Catalan regional head is speaking to the press. He says about 12 people have died and 80 people have been hospitalized.

19:04 The government of Catalonia is in crisis talks to decide what measures to take in response to the attack. 

19:01 

19:00 There are conflicting reports from Spanish media on the status of the person shot by security forces in Sant Just Desvern after running over police at a checkpoint. Some outlets say the suspect was injured, others say he was shot dead. 

18:53 The Spanish royal family condemned the attack, saying the country would not be terrorized.

"They are assassins, criminals who won't terrorise us. All of Spain is Barcelona," the royals said on Twitter. 

18:43 Police have confirmed that police exchanged fire with the driver of a Ford Focus that failed to stop at a police checkpoint.

18:38 La Vanguardia and TV-3 are reporting that one of the suspects has died in a shootout with police.

18:35 More world leaders are weighing in on the attack. British Prime Minister Theresa May says her country stands with Spain against terror, while the President of the European Council Jean-Claude Juncker says "We will never be cowed by such barbarism."

18:27 Police are evacuating all buildings on Las Ramblas. 

18:24 The interior ministry has just confirmed that 13 people have died in the attack and that at least 50 people were injured. 

18:14 Police said they have arrested one person and have denied reports of anyone being holed up in a bar or restaurant in Barcelona. "There is no individual in a bar in the center of Barcelona. We have detained one person and we are treating it as a terrorist attack," police said on Twitter. 

18:10 Local outlets are now reporting that police were struck by cars at two separate road blocks in Barcelona. El Pais reports that a Ford Focus struck three officers and got away. At a second road block a car struck one officer but the driver was arrested, it reported.

18:09 Local outlets are reporting that if tourists' hotels are in the cordoned-off area then the Barcelona tourism board is offering alternative accommodation.

18:08 

18:05 French President Emmanuel Macron says on Twitter: "All my thoughts and the solidarity of France are with the victims of the tragic attack in Barcelona. We remain united and determined." 

18:03 US President Donald Trump has condemned the attack in Barcelona. 

18:01 Some taxi operators are reportedly offering free rides to evacuate people from the area.

17:58 US Secretary of State Rex Tillerson said his office would monitor the situation.

"Terrorists around the world should know that the US and our allies are resolved to find you and bring you to justice," Tillerson told a press conference. 

17:43 Germany's Foreign Minister Sigmar Gabriel also shared his condolences on Twitter.

17:42 Germany's main government spokesman, Steffen Seibert,‏ shared his condolences with Barcelona. "We are in deep mourning for the victims of the repulsive attack in Barcelona. We stand side-by-side in solidarity with the Spanish" he wrote. 

17:36 Various local outlets are reporting that police have found a second van related to the attack outside a Burger King in the town of Vic about 69 kilometers (43 miles) north of Barcelona.

17:32 El Mundo reports that a separate vehicle has struck three police officers at a road block in Barcelona. They do not know if it is related.

17:28 Interior Councillor of Catalonia Joaquim Forn told a press conference that he could only confirm one person was killed and 32 were injured in the attack.

"It is very possible unfortunately that the number will rise, but right now we can only confirm the information from emergency medical services," he said.

17:24 A counterterrorism expert tells DW that an attack in Spain was almost inevitable from an intelligence perspective. 

"Recently numerous IS (Islamic State) suspects have been arrested in the Barcelona and Tarragona areas of Catalunia by a combined effort of Spanish National Police Forces and Moroccon counter-terrorist units," said Tomas Olivier, who is responsible for counterterrorism, intelligence and investigations at the Netherlands-based security company Twickelerveld Intelligence and Investigations.  

"Heightened awareness and pressure most likely resulted in this combined vehicle and small arms fire (SAF) attack. A terrorist response to effective intelligence work and policing we have witnessed before, for example at Zaventem (22 March 2016), were the 'Abrini cell' basically executed an attack prior to the risk to be arrested by the authorities."

17:08 Police have only comfirmed that at least one person was killed. It said 32 people were injured, 10 of them gravely so. 

16:58 Emergency services are repeating their calls for people to stay inside unless it is absolutely necessary.

16:54 Police have confirmed that it was a terror attack. 

16:52 Various Spanish outlets have increased their death tolls. La Vanguardia reports at least 12 people dead. El Pais reports close to 10, while El Mundo and La Cadena SER radio reports at least 13 dead.

16:48 Eyewitness Jesus Garcia tells Barcelona daily El Pais: "We were at the doors of the Hard Rock Cafe and going in the direction of La Rambla when we saw a white van collide with people. We saw people flying through the air after being hit. Also three cyclists flew into the air." 

16:46 Police are now saying that the motive for the incident was unclear. However, it is being treated as a terrorist incident in terms of the emergency response to it.

16:43 The US State Department has issued a warning for Barcelona, advising its citizens to avoid the area. 

16:37 Spanish media are reporting that the registration number of the vehicle has been released. The vehicle reportedly travelled 600 meters (2,000 feet) in a zig zag pattern.

16:35 

16:30 Social media users are posting more unverified images from the scene.

16:25 Police confirmed there were multiple fatalities from the attack, and said reports of a shoot-out at a major department store were false. 

16: 23 Witness Ethan Spibey told Sky News: "All of sudden it was real chaos. People just started running screaming, there were loud bangs. People just started running into shops, there was a kind of mini-stampede where we were, down one of the alleyways."

He said he as holed up in a nearby church with dozens of other people.

"They've locked the doors because I'm not sure whether the person who may have done it has actually been caught, so they've locked the doors and told people just to wait in here."

16:15 Local media are reporting that the alleged perpetrators of the attack are holed in the Rey de Estambul restaurant. Police said they were still searching for the attackers.

16:00 Local journalist Jose Miguel Calatayud told DW that 20 to 25 people were injured, according to police sources. 

15:30 The Catalonian regional police force tweeted that a person driving a small white truck had run into a crowd. It said several people were injured and later confirmed it was being treated as a terrorist attack.

Eyewitnesses posted verified images and videos of the site on Twitter. People ran away from the site and took refuge in shops in the area.

Prime Minister Mariano Rajoy said in a Tweet he was in contact with authorities and that the priority was to attend to the injured and to aid security forces.

Emergency services requested that train and metro stations close. They also requested that people in the area stay inside until told to leave.

Police asked people to avoid the zone around Las Ramblas to avoid hindering emergency responders.

Public events in relation to the Festival of Gracia have been canceled, a festival that runs from 15 - 21 of August in Barcelona. 

cb, aw, mm/rt (Reuters, AFP, dpa, AP, EFE)