Twenty three South Korean men were arrested in Cambodia on suspicion of running an Internet gambling operation inside two rented houses.

Local media The Cambodia Daily reported that members of the anti-terrorism police raided two homes in Sen Sok district in Phnom Penh, the capital and largest city of Cambodia.

Authorities told reporters the men were accused of using VoIP technology “to extort money from people in South Korea,” after investigators discovered a large volume of outgoing calls from the two residential properties.

A court clerk told the news outlet the men were facing charges of facilitating illegal online gambling.