Chinese police arrested 802 people on suspicion of child trafficking and rescued 181 children in a major operation spanning 15 provinces, the Chinese Ministry of Public Security said Friday.

The recent operation broke up two trafficking rings and led to the arrests of the ring leaders, the ministry said in a statement posted on its website.

Trafficking in children is a big problem in China. Its strict one-child policy — which limits most urban couples to one child and rural couples to two if their first-born is a girl — has driven a thriving market in babies, especially boys because of a traditional preference for male heirs.

Many trafficked babies are abducted, but some are sold by families who are too poor to care for a baby or do not want a baby girl.

The national operation was set up earlier this year after local police spotted apparent signs of trafficking, including frequent appearances of out-of-town pregnant women in a clinic in north China's Hebei province, the ministry said. State media reported that parents wishing to sell their babies could find potential buyers through the clinic.

A doctor at the clinic was arrested, state media said. It was unclear whether the pregnant women were among those arrested.

In central China's Henan province, an inspection of a long-distance bus turned up four suspects who tried to sell four infants, the ministry said.

State media report that a baby girl can fetch 30,000 to 50,000 yuan ($4,800 Cdn to $8,000) and that a baby boy sells for 70,000 to 80,000 yuan ($11,200 Cdn to $12,800). Last year, China rescued more than 8,000 children who were abducted or willingly sold by parents.

Chinese courts often hand down harsh punishments, including death sentences, to child traffickers.