Police have arrested 37 South Koreans on suspicion of running illegal gambling websites, with stakes of hundreds of billion won, in Malaysia after they were extradited from the Southeast Asian country, the National Police Agency said Thursday.

The 37 people from two illegal gambling rings -- one with nine members and the other with 28 members -- were extradited through Incheon airport, west of Seoul, from July 9 through Wednesday.

It marked the largest number of South Koreans ever arrested overseas for operating illegal gambling websites.

The nine-member ring led by a 41-year-old man with the surname Lee is suspected of operating an online gambling den in Kuala Lumpur since March 2015 and took illegal profits of 19.2 billion won ($16.25 million) by operating illegal gambling websites with around 384 billion won.

The other ring, led by a 38-year-old man with the surname Roh, is alleged to have operated similar illegal gambling websites in the Malaysian capital since April 2017.

The arrest of illegal gambling operators came after South Korean police met a Malaysian delegation at an international cybercrime symposium in Seoul in May this year. The National Police Agency provided the delegation with clues leading to their arrests.

The information obtained from South Korea helped Malaysian police learn about their hideouts. Malaysian police proposed to their South Korean counterparts that they conduct a joint raid on the hideouts.

The police agency dispatched a team of Korean investigators to Malaysia from June 20-30. In cooperation with 50 local police officers, the team managed to apprehend them and confiscated 25 computers and 40 mobile phones, subscribed under a stolen identity, that were believed to have been used in connection to the illegal gambling websites. (Yonhap)