BEIJING (AP) — China said Monday that the U.S. has "undeniable historical responsibility" in Beijing's dispute with Japan over islands in the East China Sea, marking the second straight day that it has pinned some of the blame for the tensions on Washington.

While Beijing has not asked for outside mediation, its references to the U.S. appear to be an attempt to prompt Washington to use its influence to soften the stance of Japan, which has steadfastly refused to hold talks over the islands, known as Diaoyu in China and Senkaku in Japan.

Japan argues that it has sovereignty over the islands and therefore there is nothing to negotiate. They were under U.S. control between 1945 and 1972, when they were returned to Japan, which originally annexed them in 1895. China claims sovereignty over the islands, as does Taiwan.

Washington acknowledges that the islands are under Japanese administration but doesn't take a position on who owns them. Beijing has repeatedly accused the U.S. of emboldening Tokyo by supporting its control over the islands and stating that any conflict over them would trigger the U.S.-Japan mutual defense pact.

"The U.S. bears undeniable historical responsibility," on the issue, Chinese Foreign Ministry spokesman Hong Lei said at a regular news conference Monday. "The U.S. comments ignore facts and confuse truth with untruth. China is strongly displeased and firmly opposed to it."

Tensions between Beijing and Tokyo soared in recent months after Japan's government bought the islands from private Japanese owners in September.

On Sunday, another Chinese Foreign Ministry spokesman strongly criticized the U.S. over remarks by Secretary of State Hillary Rodham Clinton reiterating longstanding U.S. policy and opposing unilateral actions that would undermine Japan's administration of the islands.

Since September, China has repeatedly sent government patrol boats to confront Japanese coast guard ships in waters surrounding the islands and earlier this month scrambled fighter jets to tail Japanese fighters that were shadowing a Chinese patrol plane.

Such actions have raised fears that an accident or miscalculation could result in a clash. China has in its recent comments stressed the need for calm and the start of talks on the issue. Japan has also reached out, with China-friendly former Prime Minister Yukio Hatoyama paying a visit last week, although it refuses to meet Chinese demands that it concede that the islands are in dispute.

In his comments, Hong said Beijing remains unswerving in its determination to assert its sovereignty, but that China and Japan were in contact on ways to ease tensions.

He urged U.S. officials to "responsibly treat the Diaoyu issue, watch their words and deeds, maintain regional stability and Sino-U.S. relations, so that the Chinese people can trust them."