A Chinese marine surveillance fleet, comprising four ships, expelled a number of Japanese Coast Guard vessels illegally sailing near the waters around the Diaoyu Islands on Tuesday, the State Oceanic Administration said in a statement.
The fleet radioed and expelled the Japanese vessels after conducting surveillance and taking photos as evidence, the online statement added.
The Associated Press said Chinese patrol boats "confronted" Japanese vessels near the disputed Diaoyu Islands on Tuesday.
Japanese Coast Guard spokesman Yuji Kito said ships from both countries flashed signs suggesting they were in their own territorial waters and demanding the other side leave. He said the situation was not more intense than previous encounters, according to the AP.
Chinese ships have sailed near the waters of the Diaoyu Islands for the 11th straight day in the latest string of similar moves, following the Japanese government's illegal purchase of the islands in early September, which sparked waves of anti-Japan protests across big Chinese cities.
Geng Xin, deputy director of the Tokyo-based Japan-China Communication Institute, told the Global Times that the encounter Tuesday is a major turn in the two countries' recent wrestling over the island disputes.
"China has used its action to achieve a new balance, in which Japan has to pay for its latest provocation (by attempting to nationalize the Diaoyu Islands)," Geng said.
China on Tuesday dismissed "self-deceiving" remarks by Japanese Foreign Minister Koichiro Gemba, which said that there is no dispute over the Diaoyu Islands, and urged the Japanese side to admit the existence of the dispute.
"The situation regarding the Diaoyu Islands has fundamentally changed following Japan's illegal purchase of the islands, which has destroyed an important consensus reached by the older generation of leaders," China's foreign ministry spokesman Hong Lei told a daily briefing.
"Japan should not have any illusions about illegally seizing the islands any more," Hong said, urging Japan to admit the dispute and solve it through negotiation.
Gemba said on Tuesday that Tokyo does not believe a territorial dispute exists over the Diaoyu Islands, according to Japanese media reports.
It is "self-deceiving" for Japan to allege that there is no dispute, Hong said.
"China's efforts are designed to demonstrate the disputes exist and then push the Japanese side to admit the disputes and return to negotiations," said Su Hao, director of the Strategy and Conflict Management Center at the China Foreign Affairs University.
"It's immature to try to solve the disputes right now. China must be prepared to deal with the conservative Japanese leadership in the long run," Su told the Global Times, adding that the dispute may last for a decade.
Japanese Prime Minister Yoshihiko Noda on Monday said in a policy speech to parliament that his administration would "strengthen security" around its coasts with "an unflagging resolve."
His remarks came after Japan said on Friday that it will spend 17 billion yen ($213 million) to purchase patrol ships and helicopters to beef up its coastguard.
"As Noda's days as prime minister are numbered, China must look to the next Japanese government, with Shinzo Abe of the Liberal Democratic Party likely to be the next leader," said Lü Fuhai, an independent researcher of Japanese issues.
"Despite his hawkish stance, Abe is much more assertive than Noda. The question then becomes simple: Peace or War," Lü said.
According to Kyodo News, the Japanese government announced Tuesday that Japan and the US will conduct a joint air and sea exercise from November 5 to 16. Earlier news said the exercise simulating recapturing an island was canceled in order not to provoke China.
Agencies contributed to this story