The Russian Foreign Ministry summoned the top diplomats of the United States, Britain and Canada on Tuesday in connection with what Moscow said was the three countries' "gross interference in Russia's internal affairs and activities that do not correspond to" ambassadors' diplomatic status.
The ministry did not elaborate on the reasons for the summons.
Earlier, US Ambassador Lynn Tracy declined an invitation to attend a Russian Duma meeting on US military biological activities in Ukraine as part of a commission on foreign interference into Russia's internal affairs which was set to be held Tuesday.