The US State Department said it would temporarily relocate its embassy in Ukraine from the capital, Kyiv, to the city of Lviv in the west of the country.
US Secretary of State Antony Blinken said in a statement on Monday that the move is based on the "dramatic acceleration in the buildup of Russian forces."
"We also continue our sincere efforts to reach a diplomatic solution, and we remained engaged with the Russian government following President Biden's call with President Putin and my discussion with Foreign Minister Lavrov," Blinken said.
"The path for diplomacy remains available if Russia chooses to engage in good faith ... We look forward to returning our staff to the Embassy as soon as conditions permit," he added.
The US has recently warned that a Russian invasion of Ukraine could be imminent, citing intelligence reports.
Russia has amassed some 130,000 troops and large quantities of military equipment at its border with Ukraine, prompting fears in its neighbor and Western nations that it might be planning an invasion in the near future.
While Moscow denies it has any such plans, it has made a number of demands to the US and NATO amid what it sees as threats to Russia's security as NATO expands eastward.
Notably, Russian President Vladimir Putin would like guarantees that Ukraine is not granted NATO membership — a guarantee the alliance is not ready to give.
The confrontation has triggered a flurry of diplomatic activity, with Western leaders holding talks both in Kyiv and Moscow in a bid to prevent what they fear might be the first major war in Europe in more than 70 years.
