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

Japan said a Russian surveillance plane violated its airspace three times on Monday.The Japanese Air Self-Defense Force scrambled fighters and fired flares in response.A Chinese military plane violated Japan's airspace last month.

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