Russia says it has expelled two American diplomats who it claims were working undercover for the CIA, in retaliation for the U.S. expulsion of two Russians.

The expulsions came in the wake of a scuffle between a Russian policeman and an American diplomat outside the U.S. embassy in Moscow in June. That diplomat is one of the two Americans expelled, Deputy Foreign Minister Sergei Ryabkov said Saturday.

Washington claims the policeman attacked the diplomat and the State Department on Friday announced that two Russians were expelled last month in response.

Russia claims the American tried to rush into the embassy late at night after a spying mission without presenting identification and was tackled by the policeman.