OFF BATAAN PROVINCE - Small boats of armed men in grey camouflage fatigues and balaclavas speed towards a Philippine ship before climbing aboard and scanning the deck with small rifles at the ready.
Moments later, its crew are marched away with their hands on their heads, concluding a simulation of a counter-terrorism operation in the South China Sea between the coast guards of the Philippines, and allies the United States and Japan.
Tuesday's (June 6) manoeuvre is part of an inaugural trilateral coast guard exercise between the three countries, coming at a time of growing unease over China's maritime conduct in the region.
The drill was a mock interception of a vessel carrying weapons of mass destruction, where Philippines coast guard personnel encounter armed resistance while boarding the vessel and are tasked with bringing the situation under control.
"All the exercises we do, we help one another to prepare for anything that may possibly happen in the future," said John Ybanez, a spokesperson for the Philippine coast guard.
"We do get our assets and training from these two countries, so what they want is, they want to see how much we've improved."
The exercises in waters off Bataan province involve more than 500 coast guard personnel and also include search and rescue and counter-piracy scenarios.
Japan and the United States have frequently condemned China's militarisation and have sought to engage closer with US ally the Philippines since Ferdinand Marcos Jr took over as president last year from pro-China predecessor Rodrigo Duterte.