BEIJING (AFP) - China has launched a probe into the abduction of children allegedly born in violation of population control policies then trafficked by officials into adoptions worldwide, an official said Tuesday.

The investigation comes after Caixin magazine reported this week that family planning officials in central China's Hunan province had abducted children and sold them into adoption to the United States, the Netherlands and Poland.

The case, which is not the first to accuse Chinese family planning officials of abusing population control policies for profit, sheds further light on the uneven implementation of the country's "one-child" population control policy.

A government spokeswoman surnamed Tang in Longhui county -- an impoverished region where many of the alleged abductions took place -- confirmed to AFP that the investigation began on Monday.

According to Caixin, at least 20 children were forcefully taken away from families in Longhui who were allegedly in violation of the "one-child" policy and put up for adoption overseas.

One family claimed they had not broken the law, as it was their first child, but family planning "enforcers" nonetheless took the baby away.

"They mistook my daughter for being illegal when my wife and I were working in Shenzhen (in south China)," migrant worker Yang Libing told the magazine.

Yang said he has found his daughter, now seven years old and living in the United States.

Family planning officials in Longhui county allegedly received 1,000 yuan

($155) for each child handed over to welfare agencies, which in turn received up to $3,000 for each child put up for adoption overseas, it said.

The abductions peaked in the middle of the last decade but had been occurring for 10 years, the magazine said.

Trafficking of women and children remains a serious problem in China with many sociologists blaming its "one-child" policy for fuelling the crime.

Under the policy, aimed at controlling China's world-leading population of more than 1.3 billion, people who live in urban areas are generally allowed one child, while rural families can have two if the first is a girl.

This has put a premium on baby boys, while baby girls are often sold off, abandoned or put up for adoption.

Up to 80,000 Chinese children have been reportedly adopted by overseas families in recent decades, with most finding homes in the United States.