Japan's top naval officer said Monday he is open to resuming engagement with China's navy despite strong concerns about Chinese activities near disputed islands in the East China Sea.

Adm. Tomohisa Takei said that personnel exchanges and port visits between Japan's maritime self-defense force and China's navy were suspended several years ago and should be restarted to improve relations.

"Our door is open," Takei told the National Bureau of Asian Research, a Washington think tank.

Four years after relations between the two East Asian powers went into a nose dive, their leaders agreed this month to speed up talks on a sea and air communication system aimed at avoiding mishaps between their forces.

Takei expressed concern, however, that China was expanding its area of operations near the disputed islands administered by Japan. He described the situation as "dangerous" and said China's activities at sea and in the air risked provoking a crisis.

Japan's government said Monday it scrambled at least one fighter jet after eight Chinese warplanes passed over the Miyako Strait on Sunday, east of the Japanese-controlled Senkaku islands, which China also claims and calls the Diaoyu.

Chinese media reports said the flights were part of a routine exercise involving about 40 aircraft.

Japan has also been critical of China's assertive behavior in the South China Sea, which lies further south. Japan is not among the half-dozen governments with territorial claims there but relies on oil and gas supplies shipped through those waters.

Takei said his government plans to undertake training cruises with the U.S. Navy in the South China Sea and multilateral exercises with regional navies. But he said that did not mean Japan was planning joint patrols with its American ally.