MANILA, Philippines: United States Secretary of State Antony Blinken has said that the U.S. will defend the Philippines if it is attacked in the South China Sea, reiterating Washington's commitment to a mutual defense treaty between the two countries.

In meetings in Manila to discuss U.S.-China tensions over the visit of U.S. House of Representatives Speaker Nancy Pelosi to Taiwan, Blinken said a 70-year-old defense pact with the Philippines remains "ironclad."

"An armed attack on Philippine armed forces, public vessels and aircraft will invoke U.S. mutual defense commitments under that treaty. The Philippines is an irreplaceable friend, partner, and ally to the United States," Blinken said during a news conference.

Blinken was the most senior U.S. official to meet with new Philippines President Ferdinand Marcos Jr.

During their meeting, Marcos downplayed the diplomatic tensions over Taiwan, claiming that Pelosi's trip "did not raise the intensity" of the situation.

"We have been at that level for a good while, but we have sort of got used to the idea," Marcos said.

The relations between the two countries were strained by the close ties between previous Filipino president Rodrigo Duterte and Beijing, as well as his anti-U.S. rhetoric and threats to downgrade the two countries' military ties.

Meanwhile, Philippines foreign secretary Enrique Manalo said President Joe Biden has invited Marcos to Washington, and both sides were working to find a suitable date.

Washington was an important ally, he added, but he told Blinken the Philippines "looks at the big powers to help calm the waters," with regards to Taiwan.

"We can ill afford any further escalation of tensions," Manalo said.