A China Coast Guard ship maneuvers past a Philippine fishing boat during the distribution of fuel and food to fishers by the civilian-led mission Atin Ito Coalition, in the disputed South China Sea on May 16, 2024. Ted Aljibe, AFP/file

China took "countermeasures" against two Philippine military aircraft that flew into its airspace over the South China Sea, the foreign ministry said on Friday.

"On August 22, two Philippine military aircraft trespassed into the airspace near the Nansha Islands, including Zhubi Jiao (Subi Reef), where China is stationed," Beijing's foreign ministry told AFP in a statement.

It added that "the Chinese side took necessary countermeasures in accordance with the law, in order to protect its own sovereignty and security".

The foreign ministry did not specify what types of measures China took, describing the actions as "professional, restrained, and standardised".

"China will continue to firmly protect its own territorial sovereignty and maritime rights, and firmly oppose any infringing actions," it added.

Beijing claims almost the entire South China Sea despite an international tribunal ruling that its assertion has no legal basis.

China and the Philippines have had repeated confrontations in the waters in recent months, including around a warship grounded years ago by Manila on the contested Second Thomas Shoal.

This week, both countries confirmed that coast guard ships had collided in a pre-dawn incident near the disputed Sabina Shoal, located 140 kilometres (86 miles) west of the Philippine island of Palawan and about 1,200 kilometres from Hainan island, the closest Chinese landmass.

That clash led the United States -- a key military ally of the Philippines -- to condemn what it called China's "dangerous actions" against "lawful Philippine maritime operations".

Analysts have said Beijing's aim is to push eastwards from the Second Thomas Shoal towards the neighbouring Sabina Shoal in the Spratly Islands, encroaching on Manila's exclusive economic zone and normalising Chinese control of the area.

Both sides have in recent months stationed coast guard vessels near Sabina, where the Philippines fears China is about to build an artificial island.