The Philippines, United States and Japan kicked off their first ever joint coastguard drills on Thursday, as the nations seek to strengthen their maritime cooperation to counter China's growing assertiveness.
The week-long exercises will be held near the mouth of Manila Bay in the hotly disputed South China Sea, which Beijing claims almost entirely.
Four Philippine Coast Guard ships will be joined by a US Coast Guard cutter and a Japanese Coast Guard cruiser for manoeuvres focused on law enforcement, and search and rescue.
"As a maritime nation, Japan has a stake to uphold and protect a rules-based maritime order," said Kenichi Matsuda, deputy chief of mission for Tokyo's embassy in Manila, at the arrival ceremony for the Japanese and US vessels.
The United States has been seeking to strengthen security alliances across the Asia-Pacific region and beyond as part of efforts to deter Chinese aggression over Taiwan and the South China Sea.
Manila and Washington recently agreed to restart joint maritime patrols in the contested waterway, and also struck a deal to give US troops access to another four military bases in the Philippines.
Tokyo and Manila are in preliminary discussions over a key defence pact that would allow them to deploy troops on each other's territory for training and other operations.
It was the United States and Japan's proposal to hold the trilateral exercise, Philippine Coast Guard spokesman Armando Balilo said this week.
The United States and Japan are key suppliers of vessels used by the Philippine coastguard and navy to patrol waters off the archipelago nation.
Beijing claims sovereignty over almost the entire South China Sea, ignoring an international court ruling that its assertion has no legal basis.
© Agence France-Presse