MOSCOW (NewsNation Now) — Ukraine President Volodymyr Zelenskyy urged state officials, politicians, and business leaders who have recently left the country to return to Ukraine within 24 hours to show unity with the nation amid fears of an impending Russian invasion.

“It is your direct duty in such a situation to be with us, with the Ukrainian people. I suggest that you return to your homeland within 24 hours and stand shoulder to shoulder with the Ukrainian army, our diplomacy, and our people,” Zelenskyy said in a video address.

U.S. officials have been warning since last week that an attack could happen any day.

“We have been told that February 16 will be the day of the attack, but we will make it the day of unity,” said Zelenskyy.

This comes as the Kremlin signaled Monday it is ready to keep talking with the West about security grievances that led to the current Ukraine crisis, offering hope that Russia might not invade its beleaguered neighbor within days as the U.S. and Europe increasingly fear.

Questions remain about Russian President Vladimir Putin’s intentions. Countries around Europe are evacuating diplomats and on alert for possible imminent war amid the worst East-West tensions since the Cold War.

On a last-ditch diplomatic trip, Germany’s chancellor said there are “no sensible reasons” for the buildup of more than 130,000 Russian troops on Ukraine’s borders to the north, south and east, and he urged more dialogue. Britain’s prime minister said Europe is “on the edge of a precipice” — but added, “there is still time for President Putin to step back.”

Despite warnings from Washington, London and elsewhere that Russian troops could move on Ukraine at a moment’s notice, Monday’s meeting between Putin and Foreign Minister Sergey Lavrov suggested otherwise.

At the session with Putin, Lavrov argued that Moscow should hold more talks with the U.S. and its allies despite their refusal to consider Russia’s main security demands.

Defense Secretary Lloyd Austin is set to meet with senior military and government leaders in Belgium, Poland, and Lithuania in Brussels this week.

Moscow, which denies it has any plans to invade Ukraine, wants Western guarantees that NATO won’t allow Ukraine and other former Soviet countries to join as members. It also wants the alliance to halt weapons deployments to Ukraine and roll back its forces from Eastern Europe, demands flatly rejected by the West.

The talks “can’t go on indefinitely, but I would suggest to continue and expand them at this stage,” Lavrov said, noting that Washington has offered to conduct dialogue on limits for missile deployments in Europe, restrictions on military drills and other confidence-building measures. Lavrov said possibilities for talks “are far from being exhausted.”

His comments, at an appearance orchestrated for TV cameras, seemed designed to send a message to the world about Putin’s own position: namely, that hopes for a diplomatic solution aren’t yet dead.

Putin noted the West could try to draw Russia into “endless talks” without conclusive results and questioned whether there is still a chance to reach agreement on Moscow’s key demands. Lavrov replied that his ministry wouldn’t allow the U.S. and its allies to stonewall Russia’s main requests.

In a phone call Sunday, U.S. President Joe Biden and Zelenskyy agreed to keep pushing both deterrence and diplomacy. Zelenskyy’s office also quoted him suggesting a quick Biden visit would help — a possibility that was not mentioned in the White House summary of the call. Such a visit would be unlikely as the U.S. is now operating with a skeleton diplomatic staff in Kyiv.

During what could be a crucial week for Europe’s security, German Chancellor Olaf Scholz visited Ukraine before heading to Moscow for talks with Putin on a high-stakes diplomatic foray.

After meeting Zelenskyy, Scholz urged Russia to show signs of de-escalation and reiterated unspecified threats to Russia’s financial standing if it invades.

“There are no sensible reasons for such a military deployment,” Scholz said. “No one should doubt the determination and preparedness of the EU, NATO, Germany and the United States” in case of a military offensive.

Zelenskyy said, “It is in Ukraine that the future of the European security architecture — of which our state is a part — is being decided today.”

Kyiv residents received letters from the mayor urging them “to defend your city,” and signs appeared in apartment buildings indicating the nearest bomb shelter. The mayor says the capital has about 4,500 such sites, including underground parking garages, subway stations and basements.

Others heeded the advice of Ukraine’s leaders not to panic. Street music flooded central Maidan Square on Sunday night and crowds danced. “I feel calm. You should always be ready for everything, and then you will have nothing to be afraid of,” said Alona Buznitskaya, a model.

Some airlines canceled flights to Kyiv and troops unloaded shipments of weapons from NATO members.

NATO countries have also been building up forces in eastern Europe. Germany’s military said the first of 350 extra troops it is sending to bolster NATO forces in Lithuania were dispatched Monday. Lithuania moved diplomats’ families and some nonessential diplomatic workers out of Ukraine after the U.S. and others pulled most of their staff from embassies in Kyiv.

“It’s a big mistake that some embassies moved to western Ukraine,” Zelenskyy said. “It’s their decision, but ‘western Ukraine’ doesn’t exist. It’s united Ukraine. If something happens, God forbids, it (escalation) will be everywhere.”

The U.S. and its NATO allies have repeatedly warned Russia will pay a high price for any invasion — but they have sometimes struggled to present a united front. Scholz’s government, particularly, has been criticized for refusing to supply lethal weapons to Ukraine or spell out which sanctions it supports, raising questions about Berlin’s resolve. No new specifics emerged from his visit to Kyiv.

So far, NATO’s warnings appear to have had little effect: Russia has only bolstered troops and weapons in the region and launched massive drills in its ally Belarus, which also neighbors Ukraine. The West fears that the drills, which run through Sunday, could be used by Moscow as a cover for an invasion from the north.

Russia has repeatedly brushed off the concerns, saying it has the right to deploy forces on its territory.

This story is developing. Refresh for updates.

Reuters and the Associated Press contributed to this report.