Japan lodged a protest with China on Wednesday after two Chinese ships briefly entered what it regards as its territorial waters near the East China Sea islets, the latest flare-up in a long-running dispute, {非本站网址} reports.
Tokyo saw its ties with Beijing deteriorate sharply last year following its arrest of a Chinese skipper whose trawler collided with Japanese patrol boats near the isles, called Senkaku in Japan and Diaoyu in China.

The isles, also claimed by Taiwan, are located near potentially rich maritime gas reserves.

"Vice Foreign Minister (Kenichiro) Sasae summoned the Chinese ambassador and said Senkaku islands are Japan's integral territory historically and in terms of international law," Chief Cabinet Secretary Yukio Edano said."He protested firmly and demanded they prevent a recurrence," he told a regular news conference.

There was no immediate comment from China, but Japan's Coast Guard quoted the Chinese side as saying they were in Chinese waters.

The two Chinese fishing patrol boats entered the disputed waters near the isles on Wednesday morning, and stayed there for a short time, Edano said.

"Chinese fishing patrol ships approached Senkaku 12 times since the collision incident last year. What separates this from the previous 11 times is that they actually entered (Japanese) territorial waters," Edano said.

Japan's Coast Guard notified the Chinese vessels that they are in Japan's territorial waters, to which the Chinese side responded by saying they are in Chinese waters and just conducting their official duties, a Coast Guard spokeswoman said.