TOKYO: Japanese police said Monday they have arrested three people in a sex trafficking case involving Cambodian women and discovered 10 Thai women who may also be victims of the same prostitution ring.
Two Japanese men and a Thai woman were taken into custody after allegedly forcing the seven Cambodians, aged from 20 to 36, into prostitution.
The group was rescued from a restaurant in Gunma northwest of Tokyo last month after a victim made a desperate Facebook plea.
Police raided the restaurant and suspects' homes, where they found another 10 women from Thailand aged from 21 to 34.
Several of the women were detained for visa violations, a police spokesman said in the first announcement of the arrest of the trio.
"But once they are determined to be victims of human trafficking, they'll be released," he told AFP.
Japan has long been a destination for Southeast Asian women seeking higher wages who often find themselves forced into sex work or indentured labour.
The Cambodian women were lured to work at the restaurant in November with the promise of high wages by a Japanese owner who arranged visas and airfares for them, according to the Cambodian foreign ministry.
The victims told police they had been promised salaries of $3,000 a month but were instead forced into sex work.
Several other suspects are on the run, according to local media.
Last August the Philippines warned its citizens against illegally travelling to Japan in search of work, saying they risked being trafficked for sex or forced labour.
Washington's annual report on people trafficking says Japan remains a "destination, source and transit" country for human trafficking despite a recent increase in prosecutions.
"Traffickers strictly control the movement of victims using debt bondage, threats of violence or deportation, blackmail, passport retention, and other coercive psychological methods," the State Department's 2016 report says.
Japanese police rescued 49 victims of human trafficking in 2015, according to latest figures from the National Police Agency.