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

A Russian military patrol aircraft violated Japanese airspace near Hokkaido's Rebun Island on three separate occasions on Monday, prompting Japan's Self-Defense Force to dispatch aircraft in an emergency response and to fire flares.

Japanese jet fighters fired warning flares at a Russian military reconnaissance plane that violated Japan’s airspace, the first time Tokyo has taken such an aggressive stance against incursions of its airspace.

The infringements were the first by Russia in five years, according to the Japanese defense ministry. A fighter fired a warning flare in response.

The Russian aircraft intruded three times and ignored radio warnings, prompting flares from Japan’s self defense aircrafts.