The United States said Monday it is relocating its embassy in Kyiv to the western Ukrainian city of Lviv, citing a "dramatic acceleration" in the buildup of Russian forces at the country's border.

"We are in the process of temporarily relocating our Embassy operations in Ukraine from our Embassy in Kyiv to Lviv due to the dramatic acceleration in the buildup of Russian forces," Blinken said in a statement.

"The embassy will remain engaged with the Ukrainian government, coordinating diplomatic engagement in Ukraine," he said. "We are also continuing our intensive diplomatic efforts to deescalate the crisis," he said.

Blinken "strongly urged" any remaining US citizens in Ukraine to leave the country immediately.

The US Embassy building in the Ukrainian capital Kyiv seen weeks before Washington decided to relocate its embassy to the western city of Lviv on February 14, 2022 amid fears of a Russian invasion
The US Embassy building in the Ukrainian capital Kyiv seen weeks before Washington decided to relocate its embassy to the western city of Lviv on February 14, 2022 amid fears of a Russian invasion AFP / Sergei Supinsky

Staffing at the US embassy in Kyiv had already been drastically reduced after the US ordered the departure of most diplomats and halted consular services.

A small consular presence had already been put in place in Lviv, about 70 kilometers (45 miles) from the Polish border.

At the US embassy in Kyiv, a Ukrainian security official outside the gate told AFP that all Americans had left.

Lights could be seen on the ground floor, but the embassy in suburban Kyiv was not flying the flag.

The United States has warned that a Russian invasion of Ukraine could be imminent, with the West accusing Russia of having massed more than 100,000 soldiers near its borders with Ukraine.