MANILA, Philippines >> The Philippine president said today the Chinese coast guard’s use of military-grade laser that briefly blinded some of the crew aboard a Philippine patrol vessel in the disputed South China Sea was not enough for him to invoke a mutual defense treaty with the United States, but warned that such aggression should stop.

President Ferdinand Marcos Jr. told a news conference he also reminded China’s ambassador to Manila that escalating aggression and incursions into Philippine waters by Beijing’s coast guard, navy and government-backed civilian fishing fleets violate an agreement he struck with Chinese President Xi Jinping last month.

“Despite the fact that it was a military-grade laser that was pointed at our coast guard, I do not think that that is sufficient for it to trigger the Mutual Defense Treaty,” Marcos said in his first public remarks about the Feb. 6 incident involving two Chinese and Philippine coast guard vessels near the disputed Second Thomas Shoal.

Responding to a question, Marcos said he was concerned that activating the 1951 treaty would ratchet up regional tensions.

Marcos spoke to reporters in the northern resort city of Baguio where he delivered a speech before cadets and former graduates of the Philippine Military Academy and repeated a vow to defend the country’s territory amid a new territorial spat with China.

“This country will not lose one inch of its territory,” Marcos said to applause. “We will continue to uphold our territorial integrity and sovereignty in accordance with our constitution and with international law.”

“We will work with our neighbors to secure the safety and security of our peoples,” Marcos said without elaborating.

Like his predecessor, Rodrigo Duterte, Marcos has taken steps to nurture friendly ties with Beijing. He met Xi in the Chinese capital early last month to boost relations and discuss the Asian neighbors’ long-seething territorial disputes in the strategic waterway that also involve Vietnam, Malaysia, Taiwan and Brunei.

China claims the South China Sea virtually in its entirety, putting it on a collision course with other Asian claimants and separately with Washington. The U.S. lays no claims to the disputed sea but has deployed its Navy ships and fighter jets to patrol the waters, promote freedom of mobility and challenge China’s territorial claims.

The contested waters have become a delicate front in the broader rivalry between the U.S. and China in Asia and elsewhere.

In the latest flare-up, the Philippines says a Chinese coast guard ship beamed a high-grade laser to block the Philippine vessel from approaching Second Thomas Shoal, which is held by Philippine forces. The Marcos administration sent a strongly worded diplomatic protest to the Chinese Embassy in Manila and Marcos summoned Chinese Ambassador Huang Xilian on Tuesday to express his concern.

China responded by saying its coast guard ship used a hand-held laser and another light-emitting gadget to harmlessly measure the distance and speed of the Philippine vessel, which it claimed intruded into Chinese territorial waters and was warned to leave the area.

U.S. State Department spokesperson Ned Price said China’s “dangerous operational behavior directly threatens regional peace and security, infringes upon freedom of navigation in the South China Sea as guaranteed under international law.”

Washington, he said, was standing by its treaty ally Manila following the latest sea feud.

Price renewed a warning that an armed attack on Philippine military forces, public vessels or aircraft, including those of the coast guard in the South China Sea, would invoke U.S. mutual defense commitments under the 1951 treaty.

Australia, Japan, Canada, Germany, Denmark and the United Kingdom also expressed alarm following the Chinese coast guard’s use of the military-grade laser against the Philippine patrol vessel that they said threatens regional peace and stability.