"We will not invade Ukraine unless we are provoked to do that," said Russian ambassador to the European Union Vladimir Chizhov in an interview with the British newspaper The Guardian on Monday.

The words of Chizhov, who said that Moscow would be entitled to respond with a counterattack if Ukrainian forces started killing Russian citizens in eastern Ukraine, do very little to reassure international observers that war in Ukraine isn't a concrete possibility.

Russia continued its military build up on the border of Ukraine over the weekend, according to the U.S. Pentagon's spokesman said Monday John Kirby, despite Moscow's announcement that it was ending some military drills.

Russian President Vladimir Putin "continues to add forces along that border with Ukraine and in Belarus, even just over the course of the weekend, he's well north of 100,000," Kirby told CNN on Monday.

According to U.S. intelligence, the crisis at the Ukrainian-Russian border seems to be nearing a breaking point, but in Ukraine, President Zelensky is still calling for calm amid an increasingly concerning situation.

While Ukrainians keep going about their businesses, including celebrating Valentine's Day, on Sunday Washington DC warned that Russia was ready to strike at "any moment," as Russian attack helicopters were spotted buzzing only a few kilometers away from the border.

The warning was followed by a request from Zelensky for a formal meeting between Moscow, Kyiv and other members of the pan-European security body (OSCE) where the Kremlin is expected to explain "the reinforcement and movement of Russian forces along our border."

On a phone call with U.S. President Joe Biden on Sunday, Zelensky invited his U.S. counterpart to visit the Ukrainian capital. Biden's presence would "contribute to de-escalation," Zelensky said. But it's unlikely such a visit would happen, especially as Biden has just ordered most U.S.  diplomats in Ukraine to leave the country immediately.

But de-escalation efforts continue on the European side.

This morning Zelensky welcomed Germany's Chancellor Olaf Scholz to Kyiv, where the two leaders discussed what the German leader described as a "very critical" threat of a Russian invasion.

"There are no good reasons for the activities on the Ukrainian border," Scholz said during a press conference held by the two leaders.

"The sovereignty and territorial integrity of Ukraine is not negotiable. We expect Russia to take clear steps to resolve the situation," he added.

Scholz is to travel to Moscow for talks with Putin on Tuesday, about Russia's alleged military build-up at the Ukrainian border and the Kremlin's intentions. 

Meanwhile in the UK, Prime Minister Boris Johnson urged Putin to step back from "the edge of a precipice" on Monday, adding that there is still time for Russia to step back.

"You've got about 130,000 troops massing on the Ukrainian border. This is a very, very dangerous, difficult situation," Johnson told reporters.

He warned that a Russian invasion of Ukraine could happen within 48 hours and urged Western allies to "stand together and show a united front" in the face of an imminent escalation.

But Johnson also took aim at the Russo-German gas pipelines, which he said weakened the European position against Moscow. 

Johnson said "all European countries need to get Nord Stream out of the bloodstream," and "yank out that hypodermic drip-feed of Russian hydrocarbons that is keeping so many European economies going."

So far Scholz has not clearly committed to any particular position regarding whether a Russian invasion would bring an end to the Nord Stream gas pipelines connecting Russia to Western Europe, though the German chancellor has pledged solidarity with Ukraine and its Western allies.

EU leaders could hold an emergency summit on the Ukraine crisis this week, a senior EU official said on Monday. 

_{Cover image: Reuters/Gleb Garanich/File Photo}