US and Philippine forces have staged an exercise simulating the seizure of an American plane by Islamic State and a hostage rescue, as they look to refocus their military alliance towards counter-terrorism.
The five-day training exercise which ended Tuesday was the first of its kind and saw more than 400 troops, airport police and hostage negotiators create a mock hijack of a plane by an IS cell that forced it to land at Clark airport north of Manila, officials said.
Philippine Defence Secretary Delfin Lorenzana said the drill was in line with President Rodrigo Duterte's wish to refocus the two countries' 1951 mutual defence pact towards counter-terrorism and disaster relief.
Since coming to power, Duterte has sought to weaken ties with the country's former colonial ruler and pivot towards China and Russia. He previously said military exercises with America were a "humiliation" for the Philippines and threatened to sever defence ties completely.
He has since banned the Filipino military from conducting joint patrols with the US navy outside Philippine waters and trimmed the number of joint military exercises.
The latest drill was held in the shadow of a US-backed military campaign to retake the Philippines' southern city of Marawi, which was occupied by pro-IS gunmen more than four months ago.
"(It) served as a perfect opportunity to assess the needs of the new security environment in the Pacific region, especially now that terrorism has become evident in our current security landscape," Lorenzana said.
Both governments stressed there was no such known plot against aircraft by IS or its supporters.
The last hijacking in the Philippines was in May 2000, when a passenger armed with a grenade and handgun tried in vain to force a Manila-bound Philippine Airlines flight to return to the southern city of Davao.