Japan said on Monday it had protested strongly against China’s allegations its fighter jets had engaged in “dangerous and unprofessional” behavior when they scrambled at the weekend as Chinese aircraft flew between Okinawa and Miyako islands.

Chinese military aircraft flew over waterways near self-ruled Taiwan – seen by Beijing as a renegade province – on Saturday as part of long-range exercises, Taiwan said.

“I have received a report from the defense minister that the Japanese planes did not conduct any close-range interference toward the Chinese military planes … or threaten the safety of Chinese military planes or its personnel,” Chief Cabinet Secretary Yoshihide Suga said.

“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,” he said.

Suga said Japan would watch the actions of the Chinese military, “which are expanding and increasing”, and make every effort toward “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 defense ministry spokesman Yang Yujun said in a statement on Saturday that two Japanese F-15 fighter jets flew over the Miyako Strait and conducted “close range interference”, firing decoy flares and “jeopardizing the security of Chinese aircraft and pilots”.

Yang said China had grave concerns and lodged a protest over the behavior of the Japanese aircraft during what he called “routine” drills in international waters.

(Reporting by Kaori Kaneko; Writing by Linda Sieg; Editing by Paul Tait)