June 18, 2013. Donald Trump tweeted: "The Miss Universe Pageant will be broadcast live from MOSCOW, RUSSIA on November 9. A big deal that will bring our countries together!" He later added: "Do you think Putin will be going - if so, will he become my new best friend?" October 17, 2013 Trump tells chat show host David Letterman he has conducted "a lot of business with the Russians."

An FBI agent tells a tech-support contractor at the Democratic National Committee it may have been hacked. On May 18, 2016, James Clapper, the director of National Intelligence, says there were "some indications" of cyberattacks aimed at the presidential campaigns. On June 14, 2016 the DNC announces it had been the victim of an attack by Russian hackers.

Senator Jeff Sessions — an early Trump endorser who led his national security advisory committee — meets Russian Ambassador Sergey Kislyak and a group of other ambassadors at a Republican National Convention event.

Julian Assange's WikiLeaks publishes 20,000 emails stolen from the DNC, appearing to show a preference for Hillary Clinton over Senator Bernie Sanders.

The FBI announces it is investigating the DNC hack saying "a compromise of this nature is something we take very seriously."

Donald Trump is elected president of the United States. On November 9, the Russian parliament burst into applause at the news.

Russian Deputy Foreign Minister Sergey Rybakov says there "were contacts" between the Russian government and the Trump campaign during the election campaign. The Trump campaign issues a firm denial.

Trump names General Michael Flynn as his national security adviser. The former Defense Intelligence Agency chief was a top foreign policy adviser in Trump's campaign. Flynn resigned in February after failing to disclose full details of his communication with Russian Ambassador Sergey Kislyak.

Acting Attorney General Sally Yates tells White House counsel Don McGahn that Flynn made false statements regarding his calls with Kislyak. On January 30, Trump fires Yates for refusing to enforce his travel ban, which was later blocked by federal courts.

Trump says he has "total confidence" in Attorney General Jeff Sessions. Sessions announces he will recuse himself from any investigation into ties between Russia and the Trump campaign.

FBI Director James Comey confirms before the House Select Committee on Intelligence that the FBI was investigating possible links between Russia and the Trump campaign.

In a letter announcing the termination, Trump writes: "While I greatly appreciate you informing me, on three separate occasions, that I am not under investigation, I nevertheless concur with the judgment of the Department of Justice that you are not able to effectively lead the Bureau."

Deputy Attorney General Rod Rosenstein appoints former FBI Director Robert Mueller to look into Russia's interference in the 2016 election and possible collusion with the Trump campaign.

Shortly after Mueller convenes a grand jury for the investigation, the FBI seizes documents from one of Paul Manafort's properties as part of a raid for Mueller's probe. The former Trump campaigner manager stepped down in August 2016 after allegations surfaced that he had received large payments linked to Ukraine's former pro-Russian government.

Donald Trump Jr. tells the Senate Judiciary Committee he has not colluded with a foreign government. The closed-door interview relates to his June 2016 meeting with Russian lawyer Natalia Veselnitskaya, which was also attended by his brother-in-law, Jared Kushner, and then-campaign manager Paul Manafort. Trump Jr.’s emails, however, suggest the meeting was supposed to produce dirt on Clinton.

Facebook, Twitter and Google reportedly tell US media they have evidence that Russian operatives exploited platforms to spread disinformation during the 2016 US presidential election. The three companies are appear before the Senate Intelligence Committee in November 2017.

Trump and Russian President Vladimir Putin meet in Helsinki for their first-ever summit. During the trip, Trump publically contradicts the findings of US intelligence agencies who concluded that Russia interfered in the 2016 presidential election.

Attorney General Jeff Sessions resigns from his post, under reported pressure from Trump. The president then appoints a critic of the Mueller probe as his successor, but later nominates William Barr to be the next attorney general in December 2018.

Trump's former long-time personal lawyer, Michael Cohen, pleads guilty to lying to Congress about discussions in 2016 on plans to build a Trump Tower in Moscow. The FBI raided his home earlier that year in April. He would later be sentenced to three years in prison. In 2019, he tells Congress that Trump is a "racist" and a "con man."

Roger Stone, a longtime Trump associate and Republican operative, is arrested at his home in Florida for lying to Congress about having advance knowledge of plans by WikiLeaks to release emails from the Democratic Party that US officials say were stolen by Russia.

Manafort is found guilty of conspiracy charges and handed an additional sentence, bringing his total prison sentence to 7.5 years. In August 2018, a court in Virginia found him guilty of eight charges, including tax and bank fraud. He also pleaded guilty to two conspiracy counts.

Special counsel Robert Mueller submits a confidential 448-page report on the findings of his investigation to the US Justice Department. The main conclusions of the report are made public when they are given to Congress. A redacted version of the report is released to the public on April 18, though Democrats call for the full report to be released.

The final report concluded that no one involved in Trump's 2016 election campaign colluded with Russia. Attorney General William Barr said the report provided no evidence that Trump obstructed justice, but stopped short of fully exonerating the president. Reacting to the findings, Trump described the probe as an "illegal take-down that failed," and said there was "complete and total exoneration."

In late March, Mueller writes a letter expressing concerns over the way Barr portrayed his report. The attorney general says the special counsel's letter was "a bit snitty" while testifying in front of the Senate Judiciary Committee in May. Barr then cancels a subsequent appearance before the House Judicial Committee, citing "unprecedented and unnecessary" hearing conditions.

Robert Mueller's congressional testimony on the Russia probe was again inconclusive. He sometimes struggled with his answers or avoided queries. To the Democrats frustration he appeared to do little to give any encouragement to the notion that President Trump could be impeached, though he did suggest he might be prosecuted for obstruction of justice crimes after he leaves the White House.

Syria has been engulfed in a devastating civil war since 2011 after Syrian President Bashar Assad lost control over large parts of the country to multiple revolutionary groups. The conflict has since drawn in foreign powers and brought misery and death to Syrians.

Syria's army, officially known as the Syrian Arab Army (SAA), is loyal to Syrian President Bashar al-Assad and is fighting to restore the president's rule over the entire country. The SAA has been fighting alongside a number of pro-Assad militias such as the National Defense Force and has cooperated with military advisors from Russia and Iran, which back Assad.

Turkey, which is also part of the US-led coalition against IS, has actively supported rebels opposed to Assad. It has a tense relationship with its American allies over US cooperation with Kurdish fighters, who Ankara says are linked to the Kurdistan Workers' Party (PKK) fighting in Turkey. Turkey has launched multiple military offensives targeting Kurdish militias.

The Kremlin has proven to be a powerful friend to Assad. Russian air power and ground troops officially joined the fight in September 2015 after years of supplying the Syrian army. Moscow has come under fire from the international community for the high number of civilian casualties during its airstrikes. However, Russia's intervention turned the tide in war in favor of Assad.

A US-led coalition of more than 50 countries, including Germany, began targeting IS and other terrorist targets with airstrikes in late 2014. The anti-IS coalition has dealt major setbacks to the militant group. The US has more than a thousand special forces in the country backing the Syrian Democratic Forces.

The Free Syrian Army grew out of protests against the Assad regime that eventually turned violent. Along with other non-jihadist rebel groups, it seeks the ouster of President Assad and democratic elections. After suffering a number of defeats, many of its members defected to hardline militant groups. It garnered some support from the US and Turkey, but its strength has been greatly diminished.

Fighting between Syrian Kurds and Islamists has become its own conflict. The US-led coalition against the "Islamic State" has backed the Syrian Democratic Forces, an alliance of Kurdish and Arab militias. The Kurdish YPG militia is the main component of the SDF. The Kurds have had a tacit understanding with Assad.

"Islamic State" (IS) took advantage of regional chaos to capture vast swathes of territory in Iraq and Syria in 2014. Seeking to establish its own "caliphate," IS has become infamous for its fundamentalist brand of Islam and its mass atrocities. IS is on the brink of defeat after the US and Russia led separate military campaigns against the militant group.

IS is not the only terrorist group that has ravaged Syria. A number of jihadist militant groups are fighting in the conflict, warring against various rebel factions and the Assad regime. One of the main jihadist factions is Hay'at Tahrir al-Sham, which controls most of Idlib province and has ties with al-Qaeda.

Iran has supported Syria, its only Arab ally, for decades. Eager to maintain its ally, Tehran has provided Damascus with strategic assistance, military training and ground troops when the conflict emerged in 2011. The Iran-backed Lebanese Shiite militant group Hezbollah also supports the Assad regime, fighting alongside Iranian forces and paramilitary groups in the country.