Japan on Sunday accused China of "dangerous" manoeuvres above disputed areas of the East China Sea, saying a Chinese fighter flew within roughly 30 metres (100 feet) of a Japanese military aircraft.
A defence ministry spokesman said a Chinese Su-27 jet on Saturday flew close to a Japanese OP-3C surveillance plane above the waters where the countries' air defence identification zones overlap.
Another Chinese SU-27 fighter also flew close to a Japanese YS-11EB plane in the same airspace, the ministry said.
One fighter jet approached to within about 50 metres and the other was as close as 30 metres to the Japanese planes, according to the spokesman.