XI'AN -- Two local officials in northwestern China's Shaanxi Province have been detained for the misuse of authority and 11 others were dismissed from office after a woman was found to have given birth nine times in the last 23 years, the police said Friday.

Investigation found that an official surnamed Fang who in charge of family planning in Cigou Township, Ankang City, and the head of Huang'an village applied for a "second birth" permission for the woman Tang Guoying and her husband Zhang Yunqing with fake documents in late 1997.

The village head surnamed Yu took bribes from the couple and sought help from Fang before the application was approved.

Yu forged the record of conception control for the woman in 1995 when she had already given seven births.

Tang Guoying, 40, has given nine births since she began living with Zhang Yunqing in 1982 when she was only 16. Two of their daughters were adopted by relatives and another three children died young.

Another 11 officials including township heads and family planning staff were stripped off their posts for negligence and other reasons, the police said without giving details.

Earlier, Director of the National Population and Family Planning Commission Zhang Weiqing warned that the government will not slacken its family planning law enforcement and will continue to punish those who break it.

China started to practice its family planning policy in the early 1970s. Without the policy it's estimated there would have been 400 million more people in the country.

Government statistics show that there are an average of 1.8 children per couple in China. In the 1970s Chinese families were averaging six children per couple when the family planning policy was first introduced.

China's family planning policy known has the "one-child family" policy allows for some leniency. An urban couple, if both husband and wife are the only child of their families, can have a second child. Farmers in many provinces are allowed to have a second child if their first child is a girl.

Rural families in Yunnan, Qinghai, and Hainan provinces, and the Ningxia and Xinjiang autonomous regions can have two children. And there is no limit for rural families in Tibet.