A Chinese air force plane flies for drills in international airspace over the Sea of Japan, Dec. 18, 2017. Chinese air force planes Monday flew through Tsushima Strait for the first time and conducted drills in international airspace over the Sea of Japan, an air force spokesperson said. [Photo/Xinhua]

Chinese air force planes Monday flew through Tsushima Strait for the first time and conducted drills in international airspace over the Sea of Japan, an air force spokesperson said.

The drills, involving bombers, fighters, reconnaissance planes and other aircraft, were aimed to examine the high-sea combat ability of the air force, said Shen Jinke, spokesman for the Chinese People's Liberation Army (PLA) Air Force.

The drills accomplished the planned purpose and improved the air force's manoeuvring capability on the high sea, he said, adding that Chinese planes responded to interference from foreign military aircraft.

As part of the air force's annual training program, the drills are in line with international laws and practices and do not target any particular country, region or object, said Shen.

The spokesman stressed that Tsushima Strait is not territorial waters, hence all countries enjoy freedom of navigation and overflight under the United Nations Convention on the Law of the Sea.

He described the drills as "legal and reasonable."

A Chinese air force plane takes off to conduct drills in international airspace over the Sea of Japan, Dec. 18, 2017. Chinese air force planes Monday flew through Tsushima Strait for the first time and conducted drills in international airspace over the Sea of Japan, an air force spokesperson said. [Photo/Xinhua]