BEIJING (Reuters) - China's Foreign Ministry condemned on Tuesday a report by the United States State Department about China's claims in the South China Sea, saying they went against Washington's promises not to take sides in the dispute.

China claims almost all the South China Sea, believed to be rich in minerals, oil and gas, which has become one of Asia's biggest potential flashpoints. Brunei, Malaysia, the Philippines, Vietnam and Taiwan have competing and sometimes overlapping claims on parts of it.

The State Department report, issued on Friday, said that China's claims were both unclear and inconsistent.

Chinese Foreign Ministry spokesman Hong Lei said that China's rights were based on its historic claims. "The US report ignores the basic facts and international legal principles and is contrary to its promises not to take a position or sides," he told a daily news briefing. "It is not helpful to the resolution of the South China Sea issue and the peace and stability of the South China Sea. We urge the U.S. side to abide by its promises, act and speak cautiously and objectively and fairly view and deal with the relevant issue."

On Sunday, China denounced the Philippines for putting it under pressure with an international arbitration case over the disputed waters, and refused again to participate a week ahead of a deadline to respond in the case.

China has long rejected arbitration, insisting it would resolve disputes bilaterally. The tribunal has given China until Dec 15 to reply in the case.