The Japanese government has lodged a protest against South Korea and Russia after South Korean warplanes fired hundreds of warning shots at a Russian military aircraft on Tuesday, Kyodo news agency said, citing government sources.

Two Russian bombers and two Chinese bombers entered the Korea Air Defence Identification Zone (KADIZ) together early on Tuesday, South Korea's defence ministry said.

A separate Russian early warning and control aircraft later twice violated South Korean airspace over Dokdo - an island that is occupied by South Korea and also claimed by Japan, which calls it Takeshima - just after 9am (0000 GMT Monday), according to the South Korean military.

Kyodo reported that Tokyo lodged a complaint through diplomatic channels to both South Korea and Russia, saying, "We cannot accept these kinds of actions in our territory."

- Reuters