The two marine surveillance ships reached the waters around the Diaoyu Islands called Senkaku islands by Japan on Tuesday morning, state-run Xinhua news agency reported, setting off the stage for a direct confrontation between the two sides.
But, reports from Tokyo said that two ships have not entered the 12 km zone around the islands, which would prompt reactions from the Japanese coast guard vessels that were monitoring the movement of the Chinese ships.
The new crisis was sparked off by the Japanese government's decision to purchase the islands in the East China Sea from private Japanese owners, which China says is an attempt to "steal" its property.
The Japanese move prompted Chinese Foreign Minister Yang Jiechi to summon Japanese Ambassador to China Uichiro Niwa for a meeting to lodge solemn representations and strong protest against the Japanese government's illegal "buying" of the Diaoyu Islands.
Yang said that the Diaoyu Islands and their affiliated islets have been inherent territory of China since ancient times, backed by historical and legal evidence.
The Japanese government's so-called "purchase" of the islands and other unilateral actions are illegal and invalid.
The Chinese defence ministry too issued a strong statement on Tuesday asking Japan to rescind from its move to purchase the island. However, China's Foreign Ministry spokesman Hong Lei while accusing Japan of attempting to steal the islands in the East China Sea also said that the two countries should return the islands negotiating table adhering to the informal agreement reached in 1980s to not escalate the dispute.
"We demand the Japanese side let go its wrong actions and come back to the relevant consensus and understanding reached between the two countries and come back to the negotiation table for resolving the Diaoyu Islands issue," Hong said holding out an olive branch to deescalate the crisis which analysts say offer a way out.
The two countries tactfully avoided confrontation all these decades studiously adhering to the agreement but the crisis escalated after the skipper of a Chinese fishing boat was detained and charged by Japan.
He was later released following vociferous appeals from China and the two countries have been accusing each other since then.