Japan scrambled fighter jets on Sunday after 40 Chinese military aircraft strayed near its airspace.
The jets were launched after the aircraft, including surveillance planes, a Su-30 fighter and an H-6K bomber, flew along the Miyako Strait between Japan’s Miyako and Okinawa islands.
China conducted a “routine drill on the high seas” aimed at “testing far-sea combat capabilities,” Shen Jinke, the country’s spokesperson for the People’s Liberation Army Air Force said in a statement.
“Bombers and fighters of the People’s Liberation Army Air Force also conducted routine patrols in the East China Sea Air Defence Identification Zone,” the statement continued.
It comes after Japan’s defence minister, Tomomi Inada, said earlier this month that Tokyo would increase operational activity in the South China Sea with the US Navy and exercises with regional navies.
China has declared ownership over most of the South China Sea, home to a disputed group of small islands and reefs over which it has rejected claims of partial sovereignty from regional neighbours.
The waters include two island chains – the Spratlys and Paracels – as well as a number of reefs.
The islands were previously occupied by the Japanese until they surrendered at the end of the Second World War.
Japanese Prime Minister Shinzo Abe has criticised China for rejecting a July ruling by an international tribunal that said Beijing’s extensive claims to the waters had no legal basis.
Abe said on Monday that Japan would “never tolerate attempts to unilaterally change the status quo” in the disputed waters, or “wherever else in the world”, in an apparent response to the Chinese move.