TOKYO — Japan slammed on Tuesday what it called the first confirmed incursion by a Chinese military aircraft into its airspace as a "serious violation" of its sovereignty, saying Beijing was becoming "increasingly active."
China's growing economic and military clout in the Asia-Pacific region and its assertiveness in territorial disputes has rattled the United States and its allies, and Monday's incident represents a further heightening of tensions.
Japan, Washington's closest ally in the region, said it scrambled fighter jets after the two-minute incursion from 11:29 a.m. on Monday by the Y-9 surveillance aircraft off the Danjo Islands in the East China Sea.
Analysts said China was possibly probing Japan's air defense network, seeking to obtain intelligence and putting pressure on Tokyo as it expands defense cooperation with the US and other countries in the region alarmed by Beijing's behavior.
"The violation of our airspace by Chinese military aircraft is not only a serious violation of our sovereignty but also a threat to our security and is totally unacceptable," Japan's chief government spokesman Yoshimasa Hayashi told reporters.
"We refrain from giving a definite answer as to the intended purpose of the Chinese aircraft's action. However, China's recent military activities near Japan have a tendency to expand and become increasingly active," he said.
Yee Kuang Heng, a professor at the University of Tokyo, said the Y-9 aircraft "was likely probing Japan's air defense network, collecting electronic intel such as Japan's radar signals and coverage."
Naoko Aoki, a political scientist at the RAND think tank, said China might be seeking "to pressure Japan as Japan continues to try to both hedge against and engage with China to balance its security concerns with economic interests."
"The area this happened could be of significance. China claims control over a large area of the continental shelf in the East China Sea, and China may be making a point, challenging Japan's delineation method," she told Agence France-Presse (AFP).
Confrontations
The uninhabited Danjo Islands are a group of small islets also located in the East China Sea off Japan's southern Nagasaki region and are not disputed territory.
Japanese and Chinese vessels have been involved in tense incidents in other areas, in particular the remote Senkaku islands in the East China Sea claimed by Beijing, which calls them the Diaoyus.
Tokyo has reported the presence of Chinese coast guard vessels, a naval ship and even a nuclear-powered submarine in the area, and there have been a series of confrontations between Japanese coast guard vessels and Chinese fishing boats.
Two nonmilitary aircraft from China — a propeller-powered plane and a small drone — forayed into airspace near the Senkakus in 2012 and 2017, the Japan Broadcasting Corp., or NHK, reported.
Staunchly pacifist for decades, Japan has ramped up defense spending with US encouragement, moving to acquire counterstrike capabilities and easing rules on arms exports.
Tokyo is also providing funding and equipment, such as patrol vessels, to countries across the region and agreed in July on a deal with the Philippines allowing troop deployments on each other's soil.
Manila and Beijing have been involved in a series of confrontations, most recently in waters near the disputed Sabina Shoal in the South China Sea, only 140 kilometers (90 miles) west of the Philippine island of Palawan.
Beijing claims the South China Sea — through which trillions of dollars of trade passes annually — almost in its entirety despite an international court ruling that its assertion has no legal basis.
China deploys boats to patrol the busy South China Sea and has built artificial islands that it has militarized to reinforce its claims.