US fighter pilots flew with the Philippine Air Force (PAF) on joint army drills as the Southeast Asian nation faced continued pressure from neighbouring China.

Footage shows the squad of military jets flying over the West Philippine Sea - the part of the South China Sea within Philippine territory - on April 29.

The PAF said it sent three planes to participate in the 'Multilateral Maritime Cooperative Activity' between the Philippine Army and the US Pacific Air Forces.

PAF spokesman Colonel Ma. Consuelo Castillo said in a statement: 'This cooperative activity aims to strengthen collaboration and enhance interoperability between the AFP and US forces.'

The U.S. is a long-time treaty ally of the Philippines, which is currently embroiled in a territorial dispute with China over parts of the South China Sea.

Expansionist China currently lays claim over almost the entire South China Sea, one of the world's busiest sea lanes. But a United Nations-backed tribunal in 2016 deemed its claims groundless.

The Communist rogue state - accused of genocide for its crimes against the Uyghur population - has been steadily increasing its influence in recent years through investment in developing countries.