The US, Japanese and Philippine coast guard ships staged law enforcement drills in waters near the disputed South China Sea on Tuesday as Washington presses efforts to reinforce alliances in Asia amid an increasingly tense rivalry with China. The drills focused on a scenario involving the interdiction and boarding of a vessel suspected of carrying weapons of mass destruction off the Bataan Peninsula.

Shots rang out as heavily armed coast guard personnel rapidly boarded the vessel from a speedboat and herded the crew members toward the stern. A helicopter hovered as US and Japanese coast guard ships helped rescue crew members who jumped off the target vessel during the mock assault.