Three Chinese government ships Saturday entered Japanese territorial waters around disputed islands, Japan's coastguard said, hours after a veiled US warning to Beijing not to challenge Tokyo's control.

The surveillance vessels sailed in waters around the islands known as the Senkakus in Japan and Diaoyus in China for nearly five hours, the coastguard said.

The vessels had all left Japanese waters by 1:52 pm (0452 GMT) and were travelling away from the East China Sea islands, which are controlled by Tokyo but claimed by Beijing, a coastguard official said.

China has repeatedly sailed into the waters since Japan nationalised the chain in September, a move that triggered anger and demonstrations in China.

US Secretary of State Hillary Clinton, speaking at a joint news conference with Japanese Foreign Minister Fumio Kishida in Washington on Friday, said the disputed area was under Japan's administration and hence protected under a US security treaty with Tokyo.

"We oppose any unilateral actions that would seek to undermine Japanese administration," Clinton said.

Clinton did not mention Beijing directly but said: "We want to see China and Japan resolve this matter peacefully through dialogue."

"We do not want to see any action taken by anyone that could raise tensions or result in miscalculation that would undermine the peace, security and economic growth in this region," she added.

The United States insists it is neutral on the ultimate sovereignty of the islands.

China has repeatedly criticised the US position and the sending of maritime surveillance ships to the potentially gas-rich area is seen by experts as a way to contest the notion that Japan holds effective control.

Kishida took a measured tone on China, describing the relationship with Beijing as "one of the most important" for Japan.

"While Japan will not concede and will uphold our fundamental positions that the Senkaku islands are an inherent territory of Japan, we intend to respond calmly so as not to provoke China," Kishida said.