Three Chinese government ships were in waters around islands at the center of a dispute with Tokyo on Monday, the day after China issued a rebuke to the U.S. over comments seen as supporting Japan.

Japan’s coastguard said the maritime surveillance boats were in waters around a chain of Tokyo-controlled islands known as the Senkakus in Japan, which Beijing calls the Diaoyus.

China has repeatedly sent ships to the area since Japan nationalized some of the chain in September, a move that triggered a diplomatic dispute and huge anti-Japan demonstrations across China.

Beijing has also sent air patrols to the archipelago in the East China Sea, and in recent weeks both Beijing and Tokyo have scrambled fighter jets, though there have been no clashes.

On Sunday, Beijing said it was “strong dissatisfied” after Secretary of State Hillary Clinton issued a veiled warning to China not to challenge Tokyo’s control over the chain, which is believed to sit atop vast mineral reserves.

On Friday, Clinton said the U.S. opposed “any unilateral actions that would seek to undermine Japanese administration” of the islands.

The top U.S. diplomat added, “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.” (AFP)