The people of Ukraine on Wednesday celebrated Unity Day, a new public holiday announced by President Volodymyr Zelenskyy. The Ukrainian President announced it to mark the day western intelligence agencies allegedly said they’d be invaded by Russia.

In visuals posted by news agency Reuters, Ukrainians were seen unfolding a 200-meter-long national flag at the National Olympic Stadium to celebrate Unity Day. Zelenskyy had asked the people of the country to “hang our national flags, put on blue and yellow ribbons and show our unity to the whole world”.

An intense diplomatic campaign is underway to head off the crisis triggered when Russia deployed more than 100,000 troops on Ukraine’s borders, backed with fleet reinforcements and powerful artillery and missile systems.

On Tuesday, there were hopes for a breakthrough as President Vladimir Putin met Germany’s Chancellor Olaf Scholz to explore a route to a negotiated solution and Moscow said it had begun to pull back some forces.

But US President Joe Biden – who has ordered Washington’s embassy in Kyiv closed and urged Americans to leave Ukraine – demanded that Russia prove its good intentions with a verifiable withdrawal.

“Analysts indicate that they remain very much in a threatening position,” Biden said in an address on the crisis. “The United States is prepared no matter what happens. We are ready with diplomacy,” he said.

“And we are ready to respond decisively to Russian attack on Ukraine, which is still very much a possibility,” he said, warning of “powerful sanctions”.

Hours after Biden’s address, the Russian defence ministry said that military drills in Moscow-annexed Crimea had ended and that soldiers were returning to their garrisons.

Units of the Southern Military District, having completed their participation in tactical exercises, are moving to their permanent deployment points,” the ministry said in a statement

State television showed images of military units crossing a bridge linking the Russia-controlled peninsula to the mainland.