Russian air defenses downed a Ukrainian drone en route to Moscow on Monday, the city's mayor said, forcing three airports that serve the capital to temporarily restrict all incoming and outgoing flights.

Moscow mayor Sergei Sobyanin said in a statement that emergency services were working at the scene of the downed drone.

Flight restrictions were introduced and quickly lifted on Domodedovo and Zhukovsky airports, but were still in effect for Sheremetyevo airport - the city's largest - as of 1010 GMT.