US Defence Secretary Ash Carter said on Thursday (April 14) that a contingent of American warplanes, airmen and commandos would remain at a former US military base in the Philippines after the conclusion of the Balikatan military exercises on Friday (April 15).
In a news briefing here, Mr Carter announced that the US would keep five A-10C Thunderbolt ground support aircraft, three HH-60G Pave Hawk helicopters, and an MC-130H special operations aircraft, as well as some 200 airmen and their crew, at Clark air base, 100km north of the capital Manila, through the end of the month.
"They will continue joint training and conduct flight operations in the area, including the South China Sea, and lay the foundation for joint air patrols to complement ongoing air patrols… ," said Mr Carter. "We'll do this on a regular basis."
He also said a "command and control centre made of up of American personnel" - about 75 Marines, according to local reports - would also stay behind after Balikatan, Tagalog for "shoulder-to-shoulder".
"With these steps, we are making our strong alliance even stronger. Efforts to do more demonstrate America's unbreakable commitment to the defence of this nation, and the security and stability of the Asia-Pacific," he said.
Mr Carter also disclosed that the US and the Philippines had held joint patrols in the South China Sea last month (March).
Reuters reported, citing the Pentagon, that a second one occurred early this month (April), and that these would occur "regularly".
"We expect the US presence here to deter uncalled for actions by the Chinese," said the Philippines' Defence Minister Voltaire Gazmin.
The stationing of US troops in Clark is covered by a new defence deal between Manila and Washington, which the Philippine Supreme Court approved in January, allowing the US to build and operate facilities at five Philippine military bases for at least 10 years.
The deal includes the country's largest army base and four air bases, including one on the western island of Palawan, which runs for 435km along one side of the South China Sea.
That base, the Antonio Bautista air base in Puerto Princesa, will be used by the Philippines to monitor its economic zone in the South China Sea and by the Americans to protect their interests further afield, said Brigadier-General Restituto Padilla, a Philippine military spokesman.
Mr Carter said the US is considering using bases other than the five identified earlier under the Enhanced Defence Cooperation Agreement.