Police have raided a Manama restaurant to rescue three Thai women who were allegedly being kept as sex slaves, according to that country's embassy.

A Thai Embassy spokesman told the Gulf Daily News (GDN), our sister publciation yesterday (May 3) that the international sting operation had only been made possible because one of the women managed to send a message to her boyfriend in Bangkok.

Authorities sprang into action once the plea for help had been passed on by the Thai foreign ministry, resulting in the Criminal Investigation Directorate's (CID) raid on Saturday at 3.40pm.

The women, who were reportedly kept in a guarded room at the back of the restaurant, were said to be in a "state of trauma" when they were found.

"Based on the information we have gathered, they were forced into prostitution," said the spokesman.

"We would like to thank the CID who investigated the case immediately and freed three of our nationals."

All three women arrived in Bahrain last month and were lured into the flesh trade by the promise of work in the restaurant, the spokesman said.

They are due to return to Thailand today.

All Thai nationals living in Bahrain have been urged to ensure they had the proper documentation and did not become a victim of human trafficking.

"It is the duty of Thai nationals travelling abroad to ensure they have a work visa or proper documents so that they do not fall into this trap of illegal trade and prostitution," said the spokesman.

Last year, the Thailand government declared a policy of "zero tolerance" on human trafficking, in a bid to tackle the issue and create an integrated system that would address its root causes.

The latest progress report on Thailand's anti-human trafficking efforts, published by the country's foreign ministry in March, stated that last year two Thai victims of exploitation in Bahrain had been rescued.

Overall, a total of 280 human trafficking cases were investigated by the Thai authorities in 2014.

Meanwhile, Bahrain investigated 30 human trafficking cases between April 2012 and March 2013, according to a report released last year by the US State Department.

For the third consecutive year, Bahrain was placed on the US Tier 2 watchlist, meaning the government "does not fully comply with the minimum standards for the elimination of trafficking" but was "making significant efforts to do so", according to the report.

Countries which do not comply with the minimum standards for tackling human trafficking are placed in Tier 3 and are subject to US sanctions in non-humanitarian and non-trade related fields.

Earlier this year, the Labour Market Regulatory Authority pledged to launch a national dedicated hotline for victims of human trafficking. - TradeArabia News Service