This year's war games have been scaled down as Philippines President Rodrigo Duterte seeks to expand security ties with China and Russia.
The Philippines and United States on Monday launched an annual military exercise that was smaller in scale than in years past, focusing on disaster response and counterterrorism while excluding territorial defence operations and maritime security.
The changes were as instructed by Philippines President Rodrigo Duterte who has had an antagonistic stance toward the US security policies while expanding security ties with China and Russia.
Balikatan, which means "shoulder-to-shoulder" in Filipino, is an annual military exercise between the US and Philippines military forces.
This year's exercise will take place in Manila and be based on a scenario of troops responding to a super-typhoon in the Philippines.
Officials say 5,400 personnel from the both sides will be involved, or about half of 11,000 troops who took part last year.
US Ambassador Sung Kim said the exercises address global challenges.
"We recognise the need to work together to overcome the daunting challenges posed by international terror networks; we also understand that bilateral disaster response training can help save lives and help rebuild devastated communities," he said.
During a trip to Beijing last year, Duterte, a self-described socialist, announced that he was in the "ideological flow" of China's communist rulers.
Much of Duterte's criticism appeared to have been triggered by American criticism of his drug war, which has claimed thousands of lives and been condemned by rights groups as a possible crime against humanity.
Duterte responded to criticism from then-US president Barack Obama by describing him using an offensive epithet and threatening to sever defence relations completely between the two nations.
Bilateral ties have warmed under Obama's successor, Donald Trump. Last month, the US president invited Duterte to visit him at the White House. The Philippines leader has been non-committal on the invitation, saying he had a busy schedule.
Duterte is due next week to visit China for a second time as leader, and is also expected to this month travel to Moscow for a meeting with Russian President Vladimir Putin.