Russian air traffic controllers didn't give a German military plane bound for Uzbekistan a permission to fly over Russian territory.
The German Airbus was forced to abort its trip to Termez, Uzbekistan, and return to Berlin, the air force said, adding that the plane was given no reason for the refusal. German authorities are investigating the incident, it said.
The online edition of German weekly Der Spiegel reported, however, that Russian authorities said the plane lacked the typical diplomatic clearance granted to such aircraft.
Last week Russia forced Lufthansa Cargo flights bound for Kazakhstan to skirt the country's airspace, saying the airline's permits had not been renewed. It also said it wanted the freight-wing of the German national carrier to start flying to an airport in Siberia instead.