Japan protested to China on Monday over a Chinese complaint that said Japanese fighter jets had engaged in "dangerous and unprofessional" behaviour when a Chinese aircraft flew near Japanese islands during the weekend.
Taiwan said last Saturday a Chinese military aircraft flew between Japan's Okinawa and Miyako islands, a region which is claimed by Beijing as a renegade province, as a part of long-range exercises.
On Saturday, Yang Yujun, the Chinese Defence Ministry spokesman, said in a statement that two Japanese F-15 fighter jets flew over the Miyako Strait and conducted a "close- range interference", firing decoy flares and "jeopardising the security of Chinese aircraft and pilots".
According to Yang, China was highly concerned about this and lodged a protest over the Japanese aircraft move during what he called "routine" drills in international waters. However, Japan rejected China's claim of such incident.
"I have received a report from the defence minister that the Japanese planes did not conduct any close-range interference towards the Chinese military planes... or threaten the safety of Chinese military planes or their personnel," Japan's Chief Cabinet Secretary Yoshihide Suga told Reuters.
"The fact that China's military unilaterally announced something clearly different from the facts is extremely regrettable and harms the improvement of relations between Japan and China, and we have strictly protested to the Chinese side," Suga added.
Suga also said that Japan would keep an eye on the actions of the Chinese military, "which are expanding and increasing", and make every effort towards "firmly protecting our country's land, sea and air space, and, in accordance with international and domestic law, take strict measures against any invasion of our airspace".
Chinese foreign ministry spokesman Geng Shuang urged Japan on Monday to take steps to prevent "safety problems on the sea and in the air". But he did not elaborate any further regarding this issue.
