Thirty-six suspects are held under escort by police at Xichang railway station, Liangshan Yi autonomous prefecture in Sichuan province and then they are sent to prefecture's public security bureau on Monday. [Photo/CFP]

Police in southwest China's Sichuan province rescued 15 infants, some sick with colds and pneumonia, after busting a major human-trafficking ring and arresting 78 people involved in supplying babies to wealthy buyers.

The children, some only a few days old, were sent to Liangshan prefecture's welfare institute for care. While some were sick from their ordeal, most were in stable condition, the Sichuan Provincial Liangshan Prefecture Public Security Department reported on Tuesday.

Authorities said some of the children had been abducted, while others had been sold to the traffickers by their poor parents.

"We have taken the infants' blood samples and are prepared to compare them with the blood DNA kept in a national database to help them reunite with their natural parents," a police officer told China Daily.

Police were first tipped to the traffickers last June, hearing about a criminal gang headed by a Yi villager in Liangshan prefecture who had organized family members, fellow villagers and friends to seek infants in the poverty-stricken Liangshan prefecture who could be sold in Shandong province.

The gang members had "a strict management and assumed different tasks to form a complete supply chain, including trafficking infants, transporting, arranging for accommodations, as well as seeking the buyers", Liangshan police said.

Due to the case's complexity, Sichuan police reported it to the Ministry of Public Security, which assumed supervision and asked Sichuan and Shandong police to create a special investigative team.

After a two-month investigation in Shandong, the team conducted a joint action on Jan 15, arresting 66 suspects in Shandong and another 12 in Liangshan, Sichuan province.

On Monday, the infants and 36 suspects were escorted aboard a train from Shandong to Liangshan.

Authorities said some of the children had been abducted, while others had been sold to the traffickers by their poor, uneducated parents.

"Poverty is often the motive behind the sale of children in China's remote and rural areas, including Yunnan, Guizhou and Sichuan," said Chen Shiqu, director of the anti human-trafficking department at the ministry.

In such areas, some poor parents even "collude with the traffickers to sell their infants to earn money due to lack of education," Zhang Baoyan, founder of Baby Back Home, a website that helps parents track missing children, told China Daily in an earlier interview.

Chen said childless couples in comparatively well-to-do provinces, including Guangdong, Fujian and Shandong often buy or "adopt" such children because they still believe in the importance of "carrying on the family line" and "having children to support them when they become old."

"Children are not commodities, and they are banned from trafficking. We will adopt 'zero tolerance' toward such anti-social activities," Chen said.