U.S. Senator John McCain says the United States must help nations in the Southeast Asian region boost their maritime forces to counter China's “unsubstantiated” territorial claims in the South China Sea.

Speaking in Washington late Monday, the former presidential candidate said he is troubled about Beijing's increasingly assertive actions in the South China Sea, especially in waters claimed by members of the Association of Southeast Asian Nations regional bloc.

Tensions have been rising between China and several of its Asia-Pacific neighbors, including the Philippines and Vietnam, over the South China Sea, which is believed to hold vast reserves of oil and gas.

China's Global Times newspaper said in an editorial Tuesday that Vietnam is mainly to blame for the disputes, and that Beijing will resolve the matter either through negotiation or military action. A Hong Kong newspaper , meanwhile, says China has advanced the start of sea trials of a new aircraft carrier to July 1 because of the maritime tensions.

McCain said in remarks to an influential policy research group that the U.S. should assist ASEAN members to develop and deploy basic maritime systems such as early warning radar and coastal security vessels.

He said America should also help them resolve their own disputes in the South China Sea and establish “a more united front” against China.