The DSI says it has solved four out of the seven major cases of human trafficking it received in 2017, or 57%. (File photo)

The Department of Special Investigation (DSI) claimed progress Sunday in tackling special cases involving human trafficking, saying it cleared up four of seven special cases in 2017.

Pol Col Songsak Raksaksakul, deputy chief of the DSI, said the agency received seven special cases involving human trafficking, of which four were successfully completed and three remain under investigation.

He listed the three biggest human trafficking cases of the year that have now been resolved.

The first involved underage girls being forced into the flesh trade at the Phu Rua cafe and karaoke bar in Phu Rua district of Loei province.

The second involved two Thai women who were forced to work in South Korea. And the third dealt with two Moroccan women who escaped from a brothel on Sukhumvit Road.

The DSI learned from the culprits often had ties to local mafia and government officers, he said.

The agency received assistance from Nvader, a New Zealand-based NGO that works to combat sex trafficking, Pol Col Songsak said.

The information it provided helped the DSI rescue ethnic girls being smuggled into Thailand to work in the sex trade, he said.

The NGO has been working with the agency in a supportive role for years. A tip-off from Nvader paved the way for the DSI to rescue seven teenagers belonging to the Thai Yai (Shan) ethnic group from a karaoke bar in Kanchanaburi back in 2015, he said.

Over the past year, the DSI has also improved its collaboration with 13 domestic and international agencies in tackling human trafficking, he said.

Since the government began implementing a tougher policy on human trafficking, Thailand has been promoted from Tier 3 to Tier 2 on the US Trafficking in Persons Report, he said.