“I was told that an instruction had been issued, and they will be released and handed over to the Russian authorities,” the ambassador said.
France also condemned the vote held in the Ukrainian territories illegally annexed by Russia.
The FSB said two U.S. diplomats would be interrogated in connection with the case.
Russian authorities said Tuesday that fighting continued in several localities in the Russian border region of Belgorod near Ukraine.
U.S. citizens whose visas for Russia are expiring have been asked to leave the country by June 15.
