Marcos Jr earlier summoned Beijing’s envoy to express ‘serious concern’ over China’s harassment of a Philippine ship.

“The country has seen heightened geopolitical tensions that do not conform to our ideals of peace and threaten the security and stability of the country, of the region and of the world,” Marcos Jr said in a speech on Saturday.

“This country will not lose an inch of its territory,” he said.

“We will continue to uphold our territorial integrity and sovereignty in accordance with our constitution and with international law. We will work with our neighbours to secure the safety and security of our peoples,” he added.

On Tuesday, Marcos Jr summoned the Chinese ambassador to express his “serious concern” over harassment by the Chinese coastguard of a Philippine Coast Guard vessel as well as Filipino fishermen in the South China Sea.

The Philippine foreign and defence ministries had said that the Chinese vessel used a “military-grade laser” against the Philippine Coast Guard ship, which was on a mission to resupply troops based in Second Thomas Shoal, which is known as Ayungin Shoal in the Philippines.

The laser had temporarily blinded the Philippine crew on the bridge of the coastguard vessel, the ministries said. China’s foreign ministry earlier in the week had defended its coastguard’s conduct, saying the actions were according to law.

Marcos Jr also told a news conference that he had reminded China’s ambassador that escalating aggression and incursions into Philippine waters by Beijing’s coastguard, navy and maritime militia forces violated an agreement he struck with Chinese President Xi Jinping last month.

The laser-pointing incident was, he said, insufficient provocation to invoke a mutual defence treaty with the United States, which is a longstanding military ally of Manila.

“If we activated that, what we are doing is escalating, intensifying the tensions in the area and I think that would be counterproductive,” the president told reporters.

Beijing’s embassy in Manila did not respond to a request for comment on Saturday.

China claims large swaths of the South China Sea as its official maritime territory, a region where about $3 trillion in ship-borne trade passes annually. An international court ruling in 2016 found that China had no legal basis for its claims in the South China Sea.

China’s foreign ministry spokesman Wang Wenbin this week accused the Philippines and the US of engaging in “pure political drama” in taking the South China Sea case to the international court of arbitration.

The spokesperson also said that China would not be intimidated by the US.