The Kremlin and the West held out the possibility of a diplomatic path out of the Ukraine crisis, even as Russia appeared to continue preparations for a potential invasion, including moving troops and military hardware closer to its neighbor.

At a made-for-television meeting with President Vladimir Putin, Foreign Minister Sergey Lavrov signaled Monday that Russia was ready to keep talking about the security grievances that have led to the crisis.

The comments seemed designed to send a message to the world about Putin’s own position and offered some hope that war could be averted, even as Washington, London and other allies kept up their warnings that troops could move on Ukraine as soon as Wednesday.

The fears stem from the fact that Russia has massed more than 130,000 Russian troops on Ukraine’s borders to the north, south and east. It has also launched massive military drills in Belarus, an ally that also borders Ukraine.

Russia denies it has any plans to invade Ukraine, and Lavrov argued that Moscow should hold more talks, despite the West’s refusal to consider Russia’s main demands.

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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 discuss limits for missile deployments in Europe, restrictions on military drills and other confidence-building measures.

Moscow wants guarantees that NATO will not 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.

Lavrov said possibilities for talks “are far from being exhausted.”

Putin noted that the West could try to draw Russia into “endless talks” and questioned whether there is still a chance to reach agreement. Lavrov replied that his ministry would not allow the U.S. and its allies to stonewall Russia’s main requests.

The U.S. reacted coolly.

“The path for diplomacy remains available if Russia chooses to engage constructively,” White House principal deputy press secretary Karine Jean-Pierre said. “However, we are clear-eyed about the prospects of that, given the steps Russia is taking on the ground in plain sight.”

U.S. officials said the Russian military continued apparent attack preparations along Ukraine’s borders. A U.S. defense official said small numbers of Russian ground units have been moving out of larger assembly areas for several days, taking up positions closer to the Ukrainian border at what would be departure points if Putin launched an invasion.

The official spoke on condition of anonymity to discuss information not publicly released. CBS News was first to report on the movement of the units.

Maxar Technologies, a commercial satellite imagery company that has been monitoring the Russian buildup, reported increased Russian military activity in Belarus, Crimea and western Russia, including the arrival of helicopters, ground-attack aircraft and fighter-bomber jets at forward locations. The photos taken over a 48-hour period also show ground forces leaving their garrisons and combat units moving into convoy formation.

Still, Ukrainian security and defense council chief Oleksiy Danilov downplayed the threat of invasion but warned of the risk of “internal destabilization” by unspecified forces.

“Today we do not see that a large-scale offensive by the Russian Federation can take place either on (Feb.) 16th or the 17th,” he told reporters. “We are aware of the risks that exist in the territory of our country. But the situation is absolutely under control.”

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As if to show defiance, Ukrainian President Volodymyr Zelenskyy said Wednesday would be a “day of national unity,” calling on the country to display the blue-and-yellow flag and sing the national anthem in the face of “hybrid threats.”

“It is not the first threat the strong Ukrainian people have faced,” Zelenskyy said Monday evening in a video address to the nation. “We’re calm. We’re strong. We’re together.”

The country is preparing nonetheless. 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 capital has about 4,500 such sites, including underground parking garages, subway stations and basements, the mayor said.

Dr. Tamara Ugrich said she stocked up on grains and canned food and prepared an emergency suitcase.

“I don’t believe in war, but on TV the tension is growing every day, and it’s getting harder and harder to keep calm,” she said. “The more we are told not to panic, the more nervous people become.”

In a last-ditch diplomatic effort German Chancellor Olaf Scholz planned to travel to Moscow on Tuesday for talks with Putin.

One possible off-ramp emerged this week. Ukraine’s ambassador to the U.K., Vadym Prystaiko, pointed at a possibility of Ukraine shelving its NATO bid — an objective that is written into its constitution — if it would avert war with Russia.

Prystaiko later appeared to back away from the idea, but the fact that it was raised at all suggests it is being discussed behind closed doors.