Xinhua news agency quoted the police as saying they have arrested 23 suspects from the provinces of Yunnan and Henan.

The investigation into the ring began in February last year after a police officer at a railway station in Yunnan found a woman with a ticket bought with the ID of another person.

She did not know Chinese, and a man accompanying her tried to stop the police from talking to her.

The officers took the couple to a local police station for further investigation. The woman was a Vietnamese national the man had bought from two other men in Yunnan.

When the police expanded the investigation, they found there was a gang that abducted and trafficked Vietnamese women to China.

Around 75 percent of trafficking victims in Vietnam, mostly women and children, are taken to China and sold there, Nguyen Van Pha, deputy head of the National Assembly’s Justice Committee, said at a meeting last month.

Some traffickers get acquainted with poor women and students in the northern mountainous region and lure them to work as prostitutes at restaurants and karaoke and massage parlors in China, he said.

Vietnam reported there were 670 trafficking victims in 2017, down by almost half from 1,128 the previous year.

Uneducated women and children from poor areas and ethnic minority groups in the northern highlands were mainly the victims.