KYIV: US President Joe Biden said Friday he's "convinced" that Russian President Vladimir Putin has decided to launch a further invasion in Ukraine, including an assault on its capital, Kyiv, as tensions spiked along the militarized border with attacks that the West called "false-flag" operations meant to establish a pretext for invasion.
On Friday, a humanitarian convoy was hit by shelling and pro-Russian rebels evacuated civilians from the conflict zone.
A car bombing hit the eastern city of Donetsk, but no casualties were reported.
After weeks of saying the US wasn't sure if Putin had made the final decision to launch a widespread invasion, Biden said that assessment had changed, citing the Americans's "significant intelligence capability."
"As of this moment I'm convinced he's made the decision," Biden said.
"We have reason to believe that."
He reiterated that it could occur in the "coming days."
Meanwhile, the Kremlin announced massive nuclear drills to flex its military muscle, and Putin pledged to protect Russia's national interests against what it sees as encroaching Western threats.
Biden reiterated his threat of massive economic and diplomatic sanctions against Russia if it does invade, and pressed Putin to rethink his course of action.
He said the US and its Western allies were more united than ever to ensure Russia pays a price for the invasion.
While Putin held out the possibility of diplomacy, a cascade of developments this week have have further exacerbated East-West tensions and fuelled war worries.
This week's actions have fed those concerns: US and European officials, focused on an estimated 150,000 Russian troops posted around Ukraine's borders, warn the long-simmering separatist conflict in eastern Ukraine could provide the spark for a broader attack.
As a further indication that the Russians continue preparations for a potential invasion, a US defense official said an estimated 40 per cent to 50 per cent of the ground forces deployed in the vicinity of the Ukrainian border have moved into attack positions nearer the border.
That shift has been under way for about a week, other officials have said, and does not necessarily mean Putin has decided to begin an invasion.
The defense official spoke on condition of anonymity to discuss internal US military assessments.
The official also said the number of Russian ground units known as battalion tactical groups deployed in the border area had grown to between 120 and 125, up from 83 two weeks ago.
Each battalion tactical group has between 750 and 1,000 soldiers.
Vice President Kamala Harris said the US still hopes Russia will de-escalate but is ready to hit it with tough sanctions in case of an attack.
US leaders this week issued their most dire warnings yet that Moscow could order an invasion of Ukraine any day.
"We remain, of course, open to and desirous of diplomacy, but we are also committed, if Russia takes aggressive action, to ensure there will be severe consequence," Harris said at the annual Munich Security Conference.
While Russia snubbed this year's conference, lines of communication remain open: The US and Russian defence chiefs spoke Friday, and US Defence Secretary Lloyd Austin called for de-escalation, the return of Russian forces surrounding Ukraine to their home bases, and a diplomatic resolution, according to the Pentagon.
Secretary of State Antony Blinken and Russian Foreign Minister Sergey Lavrov agreed to meet next week.
Immediate worries focused on eastern Ukraine, where Ukrainian forces have been fighting pro-Russia rebels since 2014 in a conflict that has killed some 14,000 people.
A bombing struck a car outside the main government building in the major eastern city of Donetsk, according to an Associated Press journalist there.
The head of the separatists' forces, Denis Sinenkov, said the car was his, the Interfax news agency reported.
There were no reports of casualties and no independent confirmation of the circumstances of the blast.
Uniformed men inspected the burned-out car.
Broken glass littered the area, Shelling and shooting are common along the line that separates Ukrainian forces and the rebels, but targeted violence is unusual in rebel-held cities like Donetsk.
However, the explosion and the announced evacuations were in line with U.S. warnings of so-called false-flag attacks that Russia would use to justify an invasion.
Separatists in the Luhansk and Donetsk regions that form Ukraine's industrial heartland known as the Donbas said they are evacuating civilians to Russia.
The announcement appeared to be part of Moscow's efforts to counter Western warnings of a Russian invasion and to paint Ukraine as the aggressor instead.
Denis Pushilin, head of the Donetsk rebel government, said women, children and the elderly would go first, and that Russia has prepared facilities for them.
Pushilin alleged in a video statement that Ukrainian President Volodymyr Zelenskyy was going to order an imminent offensive in the area.
Metadata from two videos posted by the separatists announcing the evacuation show that the files were created two days ago, The Associated Press confirmed.
U.S. authorities have alleged that Kremlin plans included prerecorded videos as part of a disinformation campaign.
Authorities began moving children from an orphanage in Donetsk, and other residents boarded buses for Russia.
Long lines formed at gas stations as more people prepared to leave on their own.
Putin ordered his emergencies minister to fly to the Rostov region bordering Ukraine to help organize the exodus and ordered the government to offer a payment of 10,000 rubles (about USD 130) to each evacuee, equivalent to about half of an average monthly salary in the war-ravaged Donbas.
Vice President Kamala Harris on Friday heralded NATO unity during the escalating Ukraine crisis and warned Russia that the US and Western allies stood ready to respond with tough sanctions if President Vladimir Putin moves forward with an invasion of Ukraine.
In a meeting with NATO Secretary-General Jens Stoltenberg as the annual Munich Security Conference got underway, Harris thanked the alliance for "all that you have done" throughout the crisis.
"We remain, of course, open to and desirous of diplomacy, as it relates to the dialogue and the discussions we have had with Russia, but we are also committed, if Russia takes aggressive action, to ensure there will be severe consequence in terms of the sanctions we have discussed," Harris told Stoltenberg.
"And we know the alliance is strong in that regard."
Harris and her top national security aides huddled with Stoltenberg after President Joe Biden on Thursday in Washington warned that "every indication" suggests Russia is "prepared to go into Ukraine, attack Ukraine."
Russia probably has massed between 169,000 and 190,000 personnel in and near Ukraine, up from about about 100,000 on Jan.
30, said Michael Carpenter, the permanent U.S. representative to the Organisation for Security and Cooperation in Europe.
In addition to troops along the border, in neighbouring Belarus and in Crimea, he said the estimate includes Russian-led forces in eastern Ukraine and also internal security units deployed to these areas.
It was unclear if these forces were included in the most recent estimate of 150,000 troops.
Harris said it was "intentional" that she was holding her first meeting at the annual security conference with NATO's secretary general.
The administration is trying to drive the message to Putin that the crisis has only bolstered the 30-country military alliance's resolve to push back against Moscow's aggression.
Stoltenberg echoed Harris' sentiment of growing NATO unity during the crisis.
"I also welcome the fact that European allies are stepping up, also increasing their presence in the eastern border of the alliance and also investing more in defense," Stoltenberg said.
"So the reality is that North America and Europe are doing more together now that we've done for many years."
US and European officials are on high alert for any Russian attempts to create a pretext for invasion.
Officials are concerned that increased shelling in the Donbas region, the slice of land where Russian-backed separatists have battled for years against the Ukrainian government, could be used by the Kremlin as a pretext to launch an invasion of Ukraine.
Harris met with Latvian President Egils Levits, Lithuania President Gitanas Nauseda, and Estonian Prime Minister Kaja Kallas to discuss the latest developments related to Russia's buildup on Ukraine's border and US readiness to further reinforce NATO allies on the eastern flank of the alliance.
Harris underscored to the Baltic leaders, who are watching the situation on the Ukraine-Russian border warily, that the Biden administration is committed to a central tenet of the NATO alliance: the principle of mutual defense.
"Our position has always been and will continue to be that Article 5 is ironclad and the spirit behind it, an attack on one is an attack on all, remains our perspective," said Harris, referring to the charter that spells out the mutual defense provision.
"I do believe our greatest strength is our unity."
Nauseda urged the US, which has bolstered its troops presence in the Baltics in recent weeks, to do even more and create a "permanent presence" in Lithuania Currently, the US deploys a small contingency of troops to the country on a rotational basis.
"I would say it is critically important for the security of our region to see more presence of United States troops," Nauseda said.
Kallas echoed the call for a greater US presence in the Baltic countries.
"We have lost our independence to Russia once, and we don't want it to happen again," she said.
Harris is set to deliver a major address at the conference on Saturday that will focus on the Ukraine crisis.
Preparations for the address were fluid, but Harris in part is expected to spotlight the unity of NATO and Western allies in the face of the Ukraine crisis, the administration official said.
Meanwhile, Biden planned to speak by phone Friday with trans-Atlantic leaders about the Russian military buildup and continued efforts at deterrence and diplomacy.
Secretary of State Antony Blinken was also in Munich on Friday where he was meeting with his counterparts from Britain, France and Germany.
Blinken is also scheduled to meet one-on-one with Qatari Deputy Prime Minister and Minister of Foreign Affairs Mohammed bin Abdulrahman Al-Thani and French Foreign Minister Jean-Ives Le Drian.