Twelve Vietnamese women have been rescued after two international human-trafficking rings were busted by China’s railway police, according to Xinhua News.

The Chinese news agency, citing a May 25 report from the police, said that 18 suspects had been arrested in a six-month-long campaign.

The investigation was launched after a suspect named Li was found smuggling a Vietnamese woman on a train from Kunming city in Yunnan province to Jinan city in Shandong province on December 12, 2014.

During the following five months, the railway police’s task force arrested 17 other suspects in Yunnan and Hunan and rescued 11 Vietnamese women in Hunan.

The police said that members of the two rings have illegally entered Vietnam and lured Vietnamese women to China by saying they were providing recruitment and matchmaking services.-VNA