The US State Department announced on Friday that it had expelled two Russian diplomats after Russia also expelled two of its officials.
"The Department will not tolerate the Russian government's pattern of harassment of our diplomats," a State Department spokesman said, adding that "unacceptable actions against our Embassy personnel in Moscow will have consequences."
On September 14, the Russian Foreign Ministry said that Jeffrey Sillin and David Bernstein, who serve as first and second secretaries at the United States Embassy in Moscow, have been declared personae non gratae due to their alleged involvement in illegal activities.
