MANILA: President of the Philippines Ferdinand Marcos Jr. summoned Beijing’s ambassador to Manila on Tuesday, after a Chinese vessel used a laser to block a coast guard ship in contested waters in the South China Sea.

The Philippine Coast Guard said on Monday that the Chinese vessel used a “military-grade laser” on Feb. 6 that temporarily blinded crew members aboard.

“The president summoned Chinese Ambassador Huang Xilian this afternoon to express his serious concern over the increasing frequency and intensity of actions by China against the Philippine Coast Guard and our Filipino fishermen,” Marcos’s office said in a statement.

Earlier in the day, the Philippines Department of Foreign Affairs lodged a diplomatic protest against China’s “aggressive activities,” saying that dangerous maneuvers, use of the laser, and illegal radio challenges by Chinese ships in the area were “disturbing and disappointing,” taking place right after Marcos’s state visit to Beijing.

During the trip last month, Marcos agreed with his Chinese counterpart Xi Jinping to establish an inter-government hotline on maritime issues amid territorial disputes in the South China Sea. China claims the strategic and resource-rich South China Sea almost in its entirety, though other countries, including the Philippines, Vietnam, Malaysia and Brunei, also have overlapping claims.

The latest incident follows increasing Chinese activity in the Philippine part of the territory, the West Philippine Sea, and came days after the Philippines granted the US expanded access to its military bases, providing American forces with a strategic footing as tensions grow over the disputed South China Sea and Taiwan.

The action was “provocative and unsafe,” US State Department spokesperson Ned Price said in a statement on Monday.

“The PRC’s dangerous operational behavior directly threatens regional peace and stability, infringes upon freedom of navigation in the South China Sea,” he said, adding that an armed attack on Philippine forces, including the coast guard in the South China Sea, would invoke US-Philippines mutual defense commitments.

Under the 1951 Mutual Defense Treaty, Washington and Manila are committed to extend military support to each other if either of them is attacked by an external party.

International security expert Stephen Cutler told Arab News that President Marcos’s foreign policy approach, which has seen his administration engaging closely not only with China and the US, but also Japan this year, may have prompted the latest Chinese aggression.

“I think it is a provocative move within the South China Sea in that area. I don’t remember hearing about this kind of activity before,” he said.

“They might be trying to send him a message to recognize their authority, recognize them as the bosses in the areas and not these other countries, and slow down the growing rapport that President Marcos and the Philippines in general are trying to establish.”