The exercises have been opposed in recent years by China, which has territorial disputes in the South China Sea with several countries, including the Philippines, and suspects the drills are part of efforts to contain Beijing.
Washington and Manila say the drills are not directed against China, and that they also focus on responding to natural disasters and humanitarian crises.
US Defense Secretary Ash Carter will fly to the Philippines to witness some of the 11-day exercises, underscoring the importance Washington puts on the joint combat drills that have been staged 32 times, said US Marine Lt. Gen. John Toolan, who heads the 5,000 American military personnel taking part in the maneuvers.
A highly mobile rocket system that has been deployed in hot spots such as Afghanistan will be used during the Balikatan, or Shoulder to Shoulder, exercises for the first time, he said.
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"We are very, very expeditionary. We can move this stuff anywhere we need to," Toolan said.
Filipino military officials said a key exercise will involve US, Australian and Philippine forces retaking an oil rig seized by hostile units in a mock assault in an unused rig off the western province of Palawan, which faces the South China Sea.
"The Philippines is the least capable armed forces in the region, and the US, being a big brother, is a big help," said Philippine Vice Admiral Alexander Lopez, who heads the contingent of about 3,500 Filipino military personnel involved in the exercises.
While many Filipinos welcome American support in strengthening the Philippines' territorial defense, left-wing activists and nationalists have opposed a growing US military presence in the former American colony, along with China's increasingly assertive advances in disputed waters.