Immigration police arrested 100 Chinese nationals in Phnom Penh on Monday for allegedly running a large online phone extortion ring.

Immigration Department investigations head Uk Hai Sela said the raid was conducted in Tuol Kork district under the oversight of Phnom Penh Municipal Court Deputy Prosecutor Sieng Sok and was based on a tip from Chinese authorities.

According to Hai Sela, the scammers would flirt with victims online and convince them to give them racy photos, which they then threatened to release to the public or loved ones unless their victims gave them money.

Nineteen women were among the 100 arrested, according to Hai Sela, who added that none were from Taiwan, which has in the past objected to the deportation of its nationals to mainland China. “Those 100 Chinese were sent to the General Department of Immigration for investigation and procedural implementation,” Hai Sela said.

Immigration officials have deported hundreds of Chinese nationals for operating so-called Voice over Internet Protocol (VoIP) scams over the years. Police arrested about 200 Chinese nationals in August in their biggest ever VoIP raid in Banteay Meanchey’s Poipet town.