Initial interrogations suggested the suburban site had been operating as a scam centre, targeting victims in China and India with sports betting and investment schemes, the commission said after the Thursday raid, which saw 137 Chinese nationals detained.

"We arrested around five Chinese bosses," commission chief Gilberto Cruz told AFP on Friday, adding they faced potential trafficking charges.

Banned by President Ferdinand Marcos last year, Philippine online gaming operators, or POGOs, are said to be used as cover by organised crime groups for human trafficking, money laundering, online fraud, kidnappings and even murder.

"This raid proves that the previous POGO workers are still trying to continue their scamming activities despite the ban," Cruz said.

He previously told AFP that about 21,000 Chinese nationals have continued to operate smaller-scale scam operations in the country since the online gaming ban.

International concern has grown in recent years over similar scam operations in other Asian nations that are often staffed by trafficking victims tricked or coerced into promoting bogus cryptocurrency investments and other cons.

President Marcos has put POGOs at the centre of recent campaign messaging in the run-up to May mid-term elections, framing predecessor Rodrigo Duterte's alleged tolerance of the sites as evidence of a too-cozy relationship with China.

Thursday's raid is the latest in a series of busts this year, including one in January that saw around 400 foreigners arrested in the capital, including many Chinese nationals.

The Washington-based think tank United States Institute of Peace said in a May 2024 report that online scammers target millions of victims around the world and rake in annual revenues of $64 billion.