Russia's Foreign Ministry on Thursday summoned U.S. envoy Lynne Tracy and declared two employees of the U.S. Embassy in Moscow persona non grata, accusing them of working with a Russian national accused of collaborating with a foreign state. 

The ministry said the two diplomats – Jeff Sillin, the embassy's first secretary, and David Bernstein, the second secretary – conducted "illegal activities by liaising with a Russian citizen, (Robert) Shonov" and must leave Russian territory within seven days. 

Shonov, who worked for the U.S. consulate in Vladivostok, was charged with allegedly passing information about the conflict in Ukraine to American diplomats, a claim the U.S. has rejected. 

(With input from agencies)