Seventeen Vietnamese women sold as brides to men in China were rescued in a series of raids on a cross-border human-trafficking network last year, the South China Morning Post reported.
Police opened the investigation in February when a couple boarding a train in the border town of Hekou, Yunnan Province, failed to pass an identity check.
The man eventually admitted the woman was from Vietnam and that he had bought her to be his wife, the report said.
Over the next few months, police conducted raids in various provinces, including Jiangxi, Anhui and Henan, to rescue trafficked women and arrest their buyers.
In all, 60 people, including traffickers and buyers, were arrested in the raids in eight Chinese provinces, the report said.
Cheap smartphones and improved mobile networks are making it easier for traffickers to use social media to befriend schoolgirls in Vietnam’s northern highlands.
The criminals earn as little as $50 for each woman they bring into China, where they are often resold far inland by middlemen, the Economist said.
Chinese police said that at their final destination, Vietnamese women can fetch from 60,000 to 100,000 yuan ($9,000-15,000).
The Vietnamese government reported nearly 13 percent increase in the number of human trafficking victims in 2016, taking the figure to 1,128 for the year.
They were sold to men seeking wives in China, Malaysia and South Korea, or just to bear children or work as prostitutes in these countries.