Nguyen Thi Duyen, 27, and Phun Van Nam, 20, natives of Quang Ninh Province that borders China, were taking the baby girl to the border on a motorbike on Thursday night, provincial border guards said Saturday. 

Suspicious border guards followed and stopped the bike, media reports said.

Duyen failed to show papers to prove the baby was hers, so the guards took her and Nam to their office.

She said that she received the baby from a woman named Phuong at a local bus station. She was asked to take the baby to a meeting point where Nam was waiting and he would drive her to China. She and Nam did not know each other earlier.

Once she got to China, Duyen would give the baby to Lan, a Vietnamese woman married to a Chinese man.

After Duyen completed her mission, Lan would send VND5 million ($214) to her bank account.

For his part, Nam said that on Thursday evening, he received a message from an unknown person asking if he could take a woman to China and get paid later. He agreed.

The border guards have transferred the baby to a healthcare center and are working with related agencies to expand the investigation.

Data from Vietnam's Ministry of Public Security shows that since 2010 there have been over 3,000 cases of human trafficking involving almost 7,000 victims, mostly women and children from poor and rural areas.

There have been more cases of newborn trafficking reported recently.

Besides the financial difficulties of the victims, experts have highlighted negligence, poor education, weak law enforcement and gender imbalance in destination countries as major factors driving human trafficking.