THE United States will defend the Philippines if the latter’s forces come under attack in the disputed South China Sea, Washington said today after a Chinese coastguard ship allegedly flashed a Philippine patrol vessel with a laser, briefly blinding some of its crew.

The Department of Foreign Affairs in Manila sent a strongly worded diplomatic protest to the Chinese embassy that “condemned the shadowing, harassment, dangerous manoeuvres, directing of military-grade laser and illegal radio challenges” by the Chinese ship.

The incident allegedly took place on February 6 when the Chinese coastguard ship beamed military-grade lasers to block the Philippine patrol vessel BRP Malapascua from approaching Second Thomas Shoal on a resupply mission to Manila’s forces there, according to Philippine officials.

Despite friendly overtures to Beijing by former Philippine president Rodrigo Duterte and his successor, Ferdinand Marcos Jnr, who met Chinese leader Xi Jinping in Beijing last month, tensions have persisted, with the US announcing tighter military ties with the Philippines this month.

Chinese Foreign Ministry spokesman Wang Wenbin said on Monday that a Philippine coastguard vessel had entered Chinese waters without permission.

Coastguard vessels responded “professionally and with restraint at the site in accordance with China’s law and international law,” he said, without elaborating or mentioning any use of laser.

US State Department spokesman Ned Price claimed that China’s “dangerous operational behaviour directly threatens regional peace and stability, infringes upon freedom of navigation in the South China Sea as guaranteed under international law and undermines the rules-based international order.”