▶ Watch Video: U.S., NATO see no sign of Russian troop pullback

Washington — The Russian government expelled the second highest-ranking American official from the U.S. Embassy in Moscow, the State Department said, as President Biden warned that the threat of a Russian invasion of Ukraine remains “very high.”

Bart Gorman, the U.S. deputy chief of mission to Russia, was expelled from the Russian capital on Thursday, a State Department spokesperson said.

“Russia’s action against [Gorman] was unprovoked and we consider this an escalatory step and are considering our response,” the spokesperson said in a statement, raising the prospect of retaliatory expulsions from Russia’s embassy in Washington.

“We call on Russia to end its baseless expulsions of U.S. diplomats and staff and to work productively to rebuild our missions,” the statement continued. “Now more than ever, it is critical that our countries have the necessary diplomatic personnel in place to facilitate communication between our governments.”

Gorman had a valid visa and had been in the country for less than three years, the spokesperson said.

The expulsion comes as the U.S. and NATO warn that Russia is preparing for an invasion and ramping up its troop presence on the Ukrainian border, despite Russian assurances earlier in the week that it was removing forces. 

Tensions ratcheted to new levels on Thursday amid reports of shelling in the Donbas region, a disputed territory in eastern Ukraine controlled by Russian-backed separatists. Both sides accused the other of violating a longstanding ceasefire, and the fighting reiterated fears that Russia could use the violence as a pretext for a broader invasion. U.S. officials have warned for weeks that Russia could conduct a “false-flag” operation to justify moving troops into Ukraine.

Speaking to reporters at the White House, Mr. Biden said he believed Russia would launch an invasion “in the next several days.”

“We have reason to believe they’re engaged in a false-flag operation to have an excuse to go in,” Mr. Biden said. “Every indication we have is they’re prepared to go into Ukraine.”