Shafaq News/ US President Joe Biden has said he is “convinced” that Russian President Vladimir Putin has decided to invade Ukraine, warning that such an attack could happen in the coming days.

Speaking from the White House on Friday afternoon, Biden said Russian troops “currently have Ukraine surrounded” and that Washington believed Moscow would target Ukraine’s capital, Kyiv.

“We have reason to believe that Russian forces are planning and intend to attack Ukraine in the coming week, in the coming days,” he told reporters. “As of this moment, I am convinced that he has made the decision.”

“Make no mistake, if Russia pursues its plans it will be responsible for a catastrophic and needless war of choice,” Biden added. “The US and our allies are prepared to defend every inch of NATO territory from any threat to our collective security, as well.”

Biden’s comments come amid increasing tensions over Russia’s troop deployment near its border with Ukraine, which for months has spurred warnings from Washington and its European allies against a possible Russian invasion.

The Kremlin insists it has no plans to invade, but Moscow has demanded security guarantees from the West to keep Ukraine and other ex-Soviet nations out of the NATO military alliance, not deploy weapons in Ukraine and pull back NATO forces from Eastern Europe.

The Biden administration has bluntly rejected Russia’s demands, and Moscow threatened to take unspecified “military-technical measures” if the West continued to stonewall.

Despite his warning, Biden on Friday once again urged Moscow to choose a path of diplomacy to reduce tensions. “Russia can still choose diplomacy. It is not too late to de-escalate and return to the negotiating table,” he said.

Al Jazeera’s Alan Fisher, reporting from Washington, said Biden’s comments were “a significant departure” from the past 72 hours, when White House officials had said they did not believe Putin had made a final decision on a possible invasion.

“So that is quite a leap for Joe Biden to say that. Quite what he’s basing that [assessment] on, we couldn’t be sure,” said Fisher, who added though that “clearly, Joe Biden sees the possibility of still being able to negotiate the way out of this crisis”.

Earlier on Friday, Ukraine’s top security official Oleksiy Danilov accused Russia of staging provocations in conflict-hit eastern Ukraine to provoke the Ukrainian military to respond. Danilov said Ukraine had no plans to recapture separatist-held territories by force, however, adding that a full-scale Russian invasion of Ukraine was unlikely.

Moscow-backed separatist leaders in eastern Ukraine said they will evacuate civilians to Russia as fears of a significant escalation in fighting grow.

The announcement by the heads of the self-proclaimed Luhansk People’s Republic (LPR) and Donetsk People’s Republic (DPR) came after the rebels and Ukraine’s government traded accusations of shelling and other ceasefire violations in Donbas.

Also on Friday, Ukraine’s military intelligence agency said it had information that Russian special forces had planted 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 Defence Intelligence of the State Security Service of Ukraine said on its official Twitter account.

The service urged Donetsk residents not to leave their homes and not to use public transport. The Russian Federal Security Service did not immediately reply to a request for comment from the Reuters news agency on Ukraine’s accusation.

Meanwhile, top Biden administration officials once more warned Russia that Washington would respond “decisively and forcefully” should Moscow decide to invade.

“The cost to Russia would be immense, both to its economy and its strategic position in the world,” Deputy National Security Advisor Daleep Singh told reporters on Friday. “Our financial sanctions have been designed to impose overwhelming and immediate costs to the largest financial institutions and state-owned enterprises in Russia”.

He added that the US administration is ready to impose export controls that would deny Russia access to “technological inputs” only produced by the US and its allies.

Separately, the US and the United Kingdom also accused Russian military hackers of being behind a spate of distributed denial of service (DDoS) attacks this week that briefly knocked Ukrainian banking and government websites offline. Russia has denied any role in the incidents.

Putin is expected to personally oversee military drills involving “strategic forces” on Saturday.

The Russian defence ministry said the exercise will include multiple practice launches of intercontinental ballistic missiles and cruise missiles. The air force, units of the southern military district, as well as the Northern and Black Sea fleets would be involved in the huge nuclear drills.