China is seriously concerned and makes "solemn representations" regarding an incident on Saturday where Japanese fighter jets closely harassed and shot decoy projectiles at Chinese air force planes，Defense Ministry spokesman Yang Yujun said in a press release.

The incident occurred when Chinese air force planes were passing through the Miyako Strait to conduct a regular exercise over the West Pacific Ocean, Yang said.

Japan scrambled two F-15 fighter jets to intercept the Chinese planes, endangering the safety of the Chinese planes and its pilots.

Chinese pilots reacted quickly, and continued to carry out the related exercise, Yang said.

“The Miyako Strait is a universally acknowledged international flight passage,” Yang said. “The exercise had been planned within this year’s air force training routine. It does not target any specific country nor objective and it adheres to international law and practices.”

The reactions from the Japanese jets were dangerous and unprofessional. It disturbed the flight freedom granted by international law, Yang added.

Numerous interference by Japanese fleets and planes in recent years could easily lead to misunderstanding and misjudgment, causing friction or even conflict in the air and at sea, Yang said.

“We urge Japan to bear maintaining regional security and the big picture of Sino-Japanese relations in mind,” Yang said. “And to take effective measures to prevent security issues in the air and at sea.”