Japan scrambled fighter jets Thursday after Russian bombers breached Japanese airspace, Agence France-Presse reported.
The two [Russian] Tu-95 planes breached airspace near the isle of Okinoshima off Fukuoka in southern Japan for nearly two minutes shortly after midday, a defense ministry spokesman said.
"A total of four F-2 planes from the Air Self-Defence Force scrambled against them," the official said.
The Japanese foreign ministry said it filed a formal protest with the Russian embassy in Tokyo over the violation and urged it to investigate.
Russian bombers also briefly breached Japanese airspace in February.