Taiwan authorities say they have arrested more than 800 people involved in a suspected trans-national phone scamming ring.

The island’s Criminal Investigation Bureau said 300 Taiwanese and 500 Chinese nationals have been arrested at hundreds of locations across Southeast Asia. The operation involved authorities in China, Taiwan, Cambodia, Indonesia, Vietnam, Laos, Malaysia, Thailand and the Philippines.

The chief of Taiwan’s Crime Investigation Bureau said more than 600 police officers were involved in the Taiwan raids alone.

He said 123 suspects were arrested on the island.

The bureau said on its website that racketeers had taken in more than $31 million from their mainly Chinese and Taiwanese victims.

Nearly 600 people were arrested across Asia as the result of a similar police investigation in June.

China and Taiwan signed an agreement in 2009 to cooperate in fighting cross-border crimes.