Two Chinese surveillance ships on Friday entered the waters near disputed islands claimed by Tokyo and Beijing for the first time after they were bought by Japan from private parties.
It is the first time for Chinese ships patrol there after the Chinese government announced on Monday the base points and baselines of the territorial waters of the Diaoyu Islands called Senkaku isles by Japan, state-run Xinhua news agency reported showing pictures of the ships close to the islands.
In all China has deployed six ships in the area which was heavily patrolled by Japanese Coast Guard vessels.
The islands are under the administrative control of Japan which bought them for USD 26 million few days to take firm control over them.
Though China has been claiming sovereignty over them for long, this is the first time its ships began patrolling the waters challenging the hold of Japan over them.
Reports from Tokyo said Japanese coast guard ships have sent telegraphic warnings to the Chinese ships.
The law enforcement and patrol activities are aimed to demonstrate China's jurisdiction over the Diaoyu Islands and its affiliated islets and ensure the country's maritime interests, the government said in statement.
Also a large number of Chinese held demonstrations before the Japanese diplomatic missions in Beijing, Shanghai and other cities.
Thursday's, China's permanent representative to UN Li Baodong met with Secretary-General Ban Ki-moon and filed a copy of the Chinese government's Diaoyu Islands baseline announcement with the United Nations.