WASHINGTON - The US and Japanese navies held joint exercises in the Philippine Sea this week, in a show of force as tensions with China and North Korea rise. Washington and Beijing are at loggerheads over a raft of issues, from chips to tariffs, but both have been alarmed by the growing assertiveness of China’s military in the Pacific. China claims self-ruled Taiwan as its own and has vowed to seize the island, by force if necessary, ramping up pressure including with major military drills in the Taiwan Strait. US Rear Admiral Carlos Sardiello called the joint exercises -- involving around a dozen US ships, including two aircraft carriers -- “a great rehearsal opportunity for us.” “Our operations here reflect an assertion of the maritime rights of all nations in accordance with international law to freedom of navigation and air operations, anywhere that is allowed,” Sardiello told reporters on the bridge of the USS Carl Vinson. “Our highly trained sailors can operate in these complex, contested domains and be lethal and survivable and execute the mission, regardless of what the threat is,” he said.