A Chinese plane intruded into Japanese airspace Thursday over the Japan-controlled, but China-claimed, Senkaku Islands in the East China Sea, Chief Cabinet Secretary Osamu Fujimura said.
The Air Self-Defense Force scrambled F-15 jets to the area after the Chinese Oceanic Administration airplane was spotted near the islet of Uotsuri at 11:06 a.m., Fujimura told reporters.
The government immediately lodged a protest with China over the incident, Fujimura said.
He said it is "extremely deplorable" that the plane entered Japanese airspace despite repeated warnings, especially after Chinese surveillance ships intruded into Japanese waters earlier Thursday.
Vice Foreign Minister Chikao Kawai summoned a Chinese envoy to the Foreign Ministry to lodge a protest.
In Beijing, officials said the move was part of Chinese patrols in the area.