WASHINGTON, Jan. 28 (Reuters) - The United States rejects China’s maritime claims in the South China Sea beyond what it is permitted under international law and stands with Southeast Asian nations resisting its pressure, U.S. Secretary of State Antony Blinken said on Wednesday.

Blinken made the remarks in a call with Philippine Foreign Minister Teodoro Locsin, the U.S. State Department said in a statement, in which he also stressed the importance of a long-standing defense agreement between the allies and its clear application if Manila came under attack in the South China Sea.

“Secretary Blinken pledged to stand with Southeast Asian claimants in the face of PRC pressure,” it said, referring to the People’s Republic of China.

“Secretary Blinken stressed the importance of the Mutual Defense Treaty for the security of both nations, and its clear application to armed attacks against the Philippine armed forces, public vessels, or aircraft in the Pacific, which includes the South China Sea,” it said.

Blinken’s assurances came after Locsin said on Wednesday the Philippines had filed a diplomatic protest over China’s passing of a law allowing its coastguard to open fire on foreign vessels, describing it as a “threat of war”.

China passed the legislation on Friday allowing its coastguard to use “all necessary means” to stop or prevent threats from foreign vessels, including demolishing other countries’ structures built on Chinese-claimed reefs.

China claims almost all of the energy-rich South China Sea, which is also a major trade route. The Philippines, Brunei, Vietnam, Malaysia and Taiwan have overlapping claims.

The United States, which has accused China of taking advantage of the distraction of the coronavirus pandemic to advance its presence in the South China Sea, has sent a carrier group through the waterway to promote “freedom of the seas”.

China on Tuesday said it would hold military drills of its own this week.

A spokesman for President Rodrigo Duterte said on Monday the Philippines hoped no country would do anything to increase tension.

The State Department said Blinken, who took office this week in Democratic President Joe Biden’s administration, “underscored that the United States rejects China’s maritime claims in the South China Sea to the extent they exceed the maritime zones that China is permitted to claim under international law.”