Japan says its warplanes used flares to warn a Russian reconnaissance aircraft to leave northern Japanese airspace.

Japan's defense minister said the use of flares was a legitimate response to airspace violation and "we plan to use it without hesitation."

Japan has protested to the Kremlin after a Russian patrol plane entered its airspace three times, Defence Minister Minoru Kihara says. “We confirmed today that a Russian Il-38 patrol aircraft has violated our airspace over our territorial waters north of Rebun Island, Hokkaido, on three occasions,” Kihara told reporters of Monday’s incidents.