US Marines amphibious assault vehicles (AAV) speed past a landing ship during an amphibious landing exercise on a beach at San Antonio in Zambales province on April 21, 2015, as part of annual Philippine-US joint maneuvers some 220 kilometres (137 miles) east of the Scarborough Shoal in the South China Sea. The Philippines voiced alarm April 20 about Chinese 'aggressiveness' in disputed regional waters as it launched giant war games with the United States that were partly aimed as a warning shot to Beijing. AFP PHOTO/TED ALJIBE        (Photo credit should read TED ALJIBE/AFP/Getty Images)