The Philippines has accused China of shining a “military grade” laser light to scuttle a resupply mission to a disputed shoal in the South China Sea.
The laser glare temporarily blinded the crew of the Filipino coast guard boat, forcing it to retreat.
The vessel was headed to a marooned navy vessel that Manila has used for years to claim the Second Thomas Shoal.
China has in the past used water cannon and sirens to enforce its claim to much of the South China Sea.
The incident, on 6 January, was only reported publicly on Monday. It was a “clear violation of Philippine sovereign rights” in waters that Manila refers to as the West Philippine Sea, the Filipino coastguard said in a statement.
Aside from flashing laser light twice, the Chinese ship also made “dangerous manoeuvres” about 150 yards (137m) from the Filipino ship’s starboard side, authorities said.
A spokesperson for President Ferdinand Marcos Jr declined to comment to the BBC. There was no immediate comment from Beijing.
In 2016, the UN’s Permanent Court of Arbitration ruled that Beijing’s sweeping claims in the South China Sea have no historical basis.
Tensions over the shoal – known as Ayungin in the Philippines – was one of the catalysts for the case, which was brought by the Philippines.
However, the tribunal has no powers to enforce its ruling and China has continued to build giant structures over reefs in the waters – which are also disputed in part by Vietnam, Malaysia, Brunei and Taiwan.
Former Philippine President Rodrigo Duterte also refused to flaunt the arbitration ruling and instead sought to repair political and economic ties between Manila and Beijing as he pivoted the country away from its long-standing ally, the US.
Mr Marcos, however, reversed the pivot. Earlier this month, his government agreed to grant the US access to four additional military bases.
In June last year, a Chinese navy vessel flashed blue lights and blinkers at a Philippine coastguard tugboat, the Philippine Daily Inquirer reported.
That incident came six months after Australia accused China of shining a military grade laser towards one of its warplanes off northern Australia.