U.S. Ambassador Michael McFaul was summoned to a morning meeting with Russia's deputy foreign secretary to hear charges embassy employee Ryan Christopher Fogle is an undercover CIA agent, RIA Novosti reported.
Fogle, who worked as a third secretary in the embassy's political department, was detained Monday on charges he attempted to recruit a Russian security services employee.
"The protest was announced to the ambassador," a terse statement issued by the Foreign Ministry said.
McFaul did not speak to reporters after leaving the meeting.
The Russian Foreign Ministry said Fogle has been ordered to leave the country as soon as possible.