The chill of a Cold War hung over Eastern Europe again Friday, with Russian military manoeuvres and drills close to Ukraine and the U.S. escalating its dire warnings about a possible Russian invasion of Ukraine, saying it could take place within days.

Diplomats and government leaders, meanwhile, struggled ever more to jumpstart moribund talks to stave off full-out war.

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Here’s a look at what is happening where and why:

Stark warnings from The White House

The White House said it still didn’t know if Russian President Vladimir Putin had made a decision to invade, but it said Putin had assembled all the elements to do so quickly and told Americans in Ukraine to leave within the next 48 hours.

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Many analysts have believed that any invasion was unlikely to start until after the Winter Olympics in China end on Feb. 20.

The heightened U.S. rhetoric followed new intelligence that showed another increase in Russian troops near the Ukrainian border.

“We can’t pinpoint the day at this point, and we can’t pinpoint the hour, but that is a very, very distinct possibility,” President Joe Biden’s national security adviser Jake Sullivan said.

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The U.S. picked up intelligence that Russia is looking at Wednesday as a target date, according to a U.S. official familiar with the findings. The official, who was not authorised to speak publicly and did so only on condition of anonymity, would not say how definitive the intelligence was.

In a demonstration of American commitment to NATO allies, the Pentagon is sending 3,000 more combat troops to Poland to join 1,700 already assembling there, a senior U.S. defence official said Friday. The official provided the information under ground rules set by the Pentagon.

The White House said Biden and Putin will discuss the crisis by phone on Saturday.

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Several NATO allies, including Britain, Norway and Denmark, are also asking their citizens to leave Ukraine.

— Aamer Madhani, Nomaan Merchant, Matthew Lee and Robert Burns in Washington

Prepping and posturing

In Romania’s Black Sea port of Constanta, the rumble of U.S. heavy military materiel was breaking the dawn quiet, signs that reinforcements and 1,000 more troops were coming into an airbase there.

It was yet another indication that hardware was being beefed up around the strategic Black Sea where Russia, Ukraine and three NATO allies have bases.

“From here in the Black Sea region, all the way to the Baltic, allies are stepping up to reinforce NATO’s presence at this critical time,” NATO Secretary-General Jens Stoltenberg said from Constanta. Romania’s neighbour Bulgaria will also welcome Spanish jets to increase the potent presence of the alliance.

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In Black Sea waters, warships of Russia’s Baltic and Northern fleets arrived in Sevastopol Bay on the Crimean Peninsula, which Russia annexed in 2014. The ships join several similar vessels that are part of Russia’s Black Sea fleet, augmenting its amphibious landing capability.

Moscow has announced sweeping drills in the Black and Azov Seas in the coming days and closed large areas for commercial shipping, drawing a strong protest from Ukraine.