WASHINGTON: The United States has ordered the families of its diplomats in the Ukrainian capital Kyiv to leave the country "due to the continued threat of Russian military action," the State Department said Sunday.

Washington has also authorized the "voluntary" departure of its embassy employees and urged US citizens in the Eastern European country to "consider departing now using commercial or other privately available transportation options."

The State Department announcement comes amid tensions between Russia and the West over European security and concerns over a possible invasion by Moscow of Ukraine.

Russia has been massing tens of thousands of troops on its border with Ukraine, along with an arsenal of tanks, fighting vehicles, artillery and missiles.

Europe threatens 'massive' sanctions if Russia attacks Ukraine

The movements have ignited stern warnings from Washington and Europe -- but so far intense diplomacy has yielded little results.

Earlier Sunday, US Secretary of State Antony Blinken dismissed the idea of slapping punitive sanctions on Moscow before any potential invasion, saying they should be used as a means of "dissuading" an attack.

"Once sanctions are triggered, you lose the deterrent effect," Blinken told CBS. "So what we're doing is putting together a whole series of actions that would figure into President (Vladimir) Putin's calculus."

That includes beefing up defenses in Ukraine with more military assistance, Blinken said.