U.S., Russian defense chiefs discuss "risk reduction" near Ukraine - Pentagon

U.S. Defense Secretary Lloyd Austin spoke on Thursday with his Russian counterpart and discussed "risk reduction near Ukraine’s borders," the Pentagon said in a brief statement.

"We're obviously still very concerned by what we're seeing," a U.S. defense official told Reuters, without commenting on the call itself.

Russia has massed some 100,000 troops near Ukraine's border. Moscow says it has no plans to invade its neighbor but President Vladimir Putin has demanded legally binding guarantees that NATO will not expand further eastwards.