Russia on Thursday said it was expelling two US embassy staff for allegedly "liaising" with Robert Shonov, a former US consulate worker accused by Moscow of spying.
Shonov, who worked for the US consulate in Vladivostok, was charged with allegedly passing information about the conflict in Ukraine to American diplomats, a claim the US has rejected.
Russia's foreign ministry said the two US diplomats -- Jeff Sillin and David Bernstein -- conducted "illegal activities by liaising with a Russian citizen, (Robert) Shonov".
"The US ambassador was told that Sillin and Bernstein must leave the territory of Russia within seven days under the status of persona non grata," it said.
Tensions between Russia and the United States have been deteriorating for years, and both sides have expelled diplomatic staff.
The United States strongly condemned Shonov's arrest in May, accusing Russia of using "increasingly repressive laws against its own citizens".