TOKYO — Japan and China blamed each other on Thursday after Tokyo raised concern that a Chinese fighter jet came dangerously close to Japanese reconnaissance planes.

The Chinese fighter jets took off from one of two Chinese aircraft carriers that were operating together for the first time in the Pacific, Japan’s Defense Ministry said.

Chief Cabinet Secretary Yoshimasa Hayashi told reporters that Japan conveyed its “serious concern” to China that such close encounters could cause accidental collisions.

According to Japan, a Chinese J-15 fighter jet took off from the Shandong aircraft carrier on Saturday and chased a Japanese P-3C aircraft on reconnaissance duty, coming within an “abnormally close distance” of 45 meters (50 yards) for about 40 minutes.

A Chinese jet also crossed 900 meters (980 yards) in front of a Japanese P-3C for about 80 minutes on Sunday, the ministry said.

Chinese Foreign Ministry spokesperson Lin Jian defended China’s activities as being fully consistent with international law and practices, and blamed Japanese vessels and airplanes for conducting close reconnaissance of China’s military activities.

The incidents occurred in the Pacific, where Japan’s Self-Defense Force spotted the two carriers, the Shandong and the Liaoning, almost simultaneously operating near southern Japanese islands for the first time.

Aircraft carriers are critical to projecting power at a distance. China routinely sends coast guard vessels, warships and warplanes around disputed East China Sea islands, but now they also reach as far as Guam, a U.S. Pacific territory with military bases.

Both Chinese carriers operated in waters off Iwo Jima, about 1,200 kilometers (750 miles) south of Tokyo. The Liaoning also sailed inside Japan’s exclusive economic zone near Minamitorishima, the country’s easternmost island, Japan’s Defense Minister Gen Nakatani said. There was no violation of Japanese territorial waters, he said.