Russia expels two U.S. embassy staff

Russian Foreign Ministry says it has summoned U.S. envoy Lynne Tracy and told her to leave within seven days .

Diplomats Jeffrey Sillin and David Bernstein are accused of working with a Russian national accused of collaborating with a foreign state.

The United States in August accused Moscow of attempting to intimidate and harass American employees.

Russia says Shonov was paid to complete tasks aimed at damaging Russia 's national security.