In a statement released Wednesday night, the National Security Council (NSC) said it had "addressed and terminated" operations taken at "the behest of Chinese intelligence", without offering details of the alleged espionage.

"For reasons of national security, we cannot discuss identities, methods, or timelines so as not to jeopardize ongoing operations," the security agency said.

"Nonetheless, necessary actions have been taken against the individuals concerned -- all Filipino nationals -- who have all confessed their complicity in espionage activities and are cooperating with authorities."

The National Security Council and the Chinese embassy in Manila did not immediately respond to AFP comment requests.

The Philippines and China have been involved in an escalating conflict over disputed areas of the South China Sea, with vessels from the two sides clashing frequently in recent years, resulting in injuries and damage.

China claims almost the entire South China Sea, brushing off rival claims from other countries -- including the Philippines -- and an international ruling that its assertion has no legal basis.

Wednesday's NSC statement cited a recent investigation in local outlet Rappler, which reported that Chinese minders had sought information about maritime deployments and resupply missions in the crucial waterway.

The Philippines last year announced multiple arrests of Chinese nationals over alleged espionage.

In April, a Chinese man was apprehended while operating a surveillance device near the offices of the Philippine election commission, authorities said, less than two weeks before the country's mid-term elections.

The man was allegedly using an "IMSI catcher", a device capable of mimicking a cell tower and snatching messages from the air in a one-to-three-kilometre (about 3,200-to-9,800-feet) radius.

Two Chinese men detained in February 2025 were accused of using the same device while driving near sensitive government and military locations in Manila.