Here’s what you need to know about Russia’s military buildup on the border with Ukraine

The tensions come as peace talks between Russia and Ukraine — as well as Russia and the United States — have stalled, increasing the threat of war. Officials from France, Germany, Russia and Ukraine are to meet in Paris on Wednesday in an effort to revive the peace process. French President Emmanuel Macron plans to present his own proposal to de-escalate the crisis to Russian President Vladimir Putin in a phone call on Friday.

Moscow annexed the Crimea region from Ukraine in 2014 and has continued to back pro-Russian separatists in the eastern part of the country. Now Russia says it is worried about NATO’s eastward expansion into what it considers its sphere of influence, with Putin demanding that Western nations bar Ukraine and other post-Soviet republics from joining the U.S.-led military alliance.

The Biden administration has vowed to inflict “enormous consequences” on Russia if it attacks Ukraine. The State Department this week also ordered all family members of U.S. Embassy personnel serving in Kyiv to leave the country because of the “threat of Russian military action.” Britain and Canada did the same.

“If [Putin] were to move in with all those forces, it’d be the largest invasion since World War II,” President Biden said Tuesday. “It would change the world.”