Separatist authorities in eastern Ukraine on Friday said they planned to evacuate their breakaway region's residents to Russia.

Denis Pushilin, head of the self-proclaimed Donetsk People's Republic, said Russia had agreed to provide accommodation for those who leave. He said women, children and the elderly should be evacuated first.

A similar announcement was made in the other self-proclaimed region, Luhansk.

A loud warning siren sounded in the center of the city of Donetsk on Friday. The separatists claim a car exploded near their government building in the city, according to the Russian state-run TASS news agency. 

Russian news outlet RIA said nobody was hurt in the explosion. 

Russian President Vladimir Putin has ordered the government to provide refuge to civilians from Donetsk and Luhansk, once they arrive in southern Russia.  

State media has reported that some of the first buses carrying evacuees from separatist-held territories have started to arrive in Russia's Rostov region.

Ukraine's national security adviser, Oleksiy Danilov said that a full-scale Russian invasion was unlikely but there would be targeted provocations taking place in eastern Ukraine.

Danilov said Kyiv would stick continue seeking peaceful measures as a way of dealing with the crisis, adding that Ukraine had no plans of moving into separatist territory. 

A joint statement from German Foreign Minister Annalena Baerbock and French Foreign Minister Jean-Yves Le Drian warned that Russia may be engaging in "staged incidents" as a "pretext for possible military escalation." 

Ukrainian intelligence claims Russian special forces have put explosives at a number of social infrastructure facilities in separatist-controlled Donetsk. 

"These measures are aimed at destabilizing the situation in the temporarily occupied territories of our state and creating grounds for accusing Ukraine of terrorist acts," the Defense Intelligence of the State Security Service of Ukraine tweeted. 

OSCE reports 'significant increase' in ceasefire violations

The Organization for Security and Co-operation in Europe (OSCE) said violations of the ceasefire in eastern Ukraine experienced a "significant increase." 

Late Friday, the OSCE said that it had recorded 870 cease fire violations in the previous day. 

While there have been instances of days with a greater number of violations, compared to previous days the uptick is significant.

OSCE reported 189 ceasefire violations in the Donetsk region alone on Thursday, up from 24 the previous day.

German armed forces raise alert level

Germany's Defense Ministry said that troops in NATO's quick reaction force would be on a heightened alert level.

This would allow for a rapid deployment to help bolster security among eastern European allies, in the event of an escalation in tensions with Russia.

"The increased readiness to deploy enables NATO, in case of a further escalation by Russia, to guarantee appropriate reassurance in particular to our eastern European allies in order to protect allied territory," the statement said.

Largest troop build-up 'since Cold War'

NATO Secretary General Jens Stoltenberg said on Friday that Europe was seeing the largest build-up of troops since the Cold War.

"There can be no doubt that we have now the biggest concentration of military forces since the end of the Cold War in Europe," Stoltenberg told German broadcaster ZDF.

The NATO chief also warned that the size of the force Russia had mustered, exceeded the amount necessary for military drills and that there was capacity to invade without warning.

Kremlin concerned by increase of violence 

Earlier on Friday, the Kremlin said it was concerned by an increase in fighting in eastern Ukraine as both Ukrainian government forces and pro-Russian rebels reported increased shelling for a second straight day.

"What is happening in the Donbass is very concerning news and potentially very dangerous," Kremlin spokesman Dmitry Peskov said.

Washington and other Western allies say such an escalation could form part of a Russian pretext to invade.

As the OSCE reported the uptick in fighting, Russian Foreign Minister Sergey Lavrov accused the monitoring mission of trying to gloss over ceasefire violations by Ukrainian forces.

Ukraine says no plan to advance

Ukraine's defense minister on Friday said there was no plan for the country's armed forces to attack eastern separatists or launch an operation to reclaim the Russian-annexed peninsula of Crimea.

Oleksiy Reznikov told parliament that Ukraine would refrain from giving Russia any reason to attack its neighbor.

"Ukraine is stepping up its defenses. Our mission is not to do any of the things the Russians are trying to provoke us into doing. We have to push back but keep a cool head," he said.

US warns of potential 'false flag' operation

US President Joe Biden warned late Thursday more Russian troops moving toward the border with Ukraine, indicating an invasion could begin within days.

The warning came after NATO allies voiced concern that Moscow was seeking a pretext for war, with some 150,000 Russian troops posted around the border with Ukraine.

Some 60% of Russia's ground forces are close to the frontier.

"Every indication we have is they're prepared to go into Ukraine, attack Ukraine," Biden told reporters at the White House. 

Biden said the US had "reason to believe" that Russia is "engaged in a false flag operation to have an excuse to go in," but he did not provide details.

During a speech Friday afternoon, Biden sought again to emphasize that a path of diplomacy remains an option available to Putin should he opt for a meaningful path of de-escalation.

Russia says tanks, jets pulled back

However, the Kremlin — which has long considered Ukraine to be part of its sphere of influence — says it does not plan to invade. 

However, it considers NATO's expansion eastward an existential threat, and is demanding that the alliance promises it will never allow Ukraine to join.

Russia on Friday said it was pulling back more tanks and other armored vehicles from areas near Ukraine's border. 

"Another military train carrying personnel and military equipment belonging to tank army units of the western military district returned to their permanent bases in the Nizhny Novgorod region after completing scheduled exercises," the Russian defense ministry said in a statement.

Moscow also said that 10 Su-24 war planes were being moved from the annexed Crimean peninsula to airfields in other regions as part of drills.

Germany urges Russia to change tack

As Western leaders arrived in Germany for the Munich Security Conference (MSC), German Foreign Minister Annalena Baerbock said Moscow needed to show "serious steps towards de-escalation."

She accused Russia — in its call for NATO to close the door to Kyiv — of making demands reminiscent of the Cold War. 

"With an unprecedented deployment of troops on the border with Ukraine and Cold War demands, Russia is challenging fundamental principles of the European peace order," Baerbock said in a statement.

This year's MSC is overshadowed by the fear of a large-scale war in Ukraine, with a meeting of the G7 foreign ministers on the crisis scheduled on the sidelines. Unlike in previous years, Russia did not send a delegation to the MSC. 

Ahead of the opening ceremony, Baerbock said, "It is a loss that Russia is not taking advantage of this opportunity."

US Vice President Kamala Harris and US Secretary of State Antony Blinken, the most senior US officials present at this year's event, arrived in Germany late Thursday.

Ischinger says Russia not threatened

The MSC's chairman Wolfgang Ischinger says there is no threat to Russia. He told German broadcaster ARD on Friday that the crisis was a result of Moscow's desire to ensure the country was surrounded by subordinate countries that would "renounce their complete independence."

"Of course, that is not acceptable," Ischinger said. "Every European state must be able to determine its own destiny. And without threatening others. No one is threatening Russia."

Spanish Foreign Minister Jose Manuel Albares also said NATO and the European Union posed no threat to Russia.

"Neither NATO nor the EU have a hidden agenda or hidden interests or anything that cannot be explained," Albares told the radio station Onda Cero. "War is totally avoidable and unnecessary."

EU 'ready to mobilize' humanitarian aid

The EU Commission vice-president, Margaritis Schinas, told German newspaper Die Welt in comments published Friday that the EU could expect anywhere between 20,000 and over one million refugees in the event of military escalation in Ukraine. 

He also said that roughly 20,000 EU citizens remain in Ukraine at present. In the event of a dramatic escalation of hostilities, they would likely need assistance to evacuate the country.

The EU is "ready to mobilize significant humanitarian aid and help with civilian protection," he said.

Poland prepared to take refugees

Meanwhile, Poland has said it is ready to help people who would be forced to leave Ukraine in the event of a Russian invasion. 

"As for the crisis that would certainly be caused if Russia attacked Ukraine, I want to stress that we are ready to help those who will be forced to leave Ukraine," said Polish Defence Minister Mariusz Blaszczak.

His comments came as US Defense Secretary Lloyd Austin announced the planned sale of 250 Abrams tanks to Poland, as Washington moves to strengthen the defenses of its eastern European ally.

Austin was due to talk with his Russian counterpart Sergei Shoigu on Friday.

Blinken and Lavrov to meet as diplomatic frenzy continues

Next week, US Secretary of State Blinken is set to meet with Russian Foreign Minister Sergey Lavrov "if there is no further invasion of Ukraine," US State Department spokesman Ned Price said late Thursday. On Friday, offficials said the meeting would take place next Thursday.

The announcement came hours after Blinken addressed the UN Security Council and warned that US intelligence shows Russian forces are preparing to attack Ukraine in the "coming days."

Price said the meeting was initiated by the US "because we believe the only responsible way to resolve this crisis is through diplomacy and dialogue." US President Joe Biden is also scheduled to speak with NATO allies Friday to continue coordinating a path for Russia to de-escalate.

Putin and Macron are scheduled to speak Sunday.

rc, kb/dj (AFP, AP, dpa, Reuters)