BEIJING -- Chinese authorities have vowed to take tough measures to control fetus gender testing and sex-selective abortions to hold back rising sex ratio imbalance.

"People who conduct illegal gender testing of fetuses and sex-selective abortions should face serious punishment," according to a statement jointly issued by the Central Committee of the Communist Party of China and the State Council.

The authorities also pledged to improve protection of baby girls, saying that people who kill, abandon or injure infant girls or ill-treat their mothers, should be severely punished.

Medical institutions that use ultra-sound technology and abortion medicines will be more closely supervised, according to the statement.

China's gender ratio for newborn babies in 2005 was 118 boys for 100 girls, compared with 110:100 in 2000. In some regions, the figure has reached 130 newborn boys for every 100 girls.

The decision said the gender-ratio imbalance which has been developing for some time amounts to "a hidden danger" for the society that will "affect social stability."

In an attempt to halt the growing imbalance, China launched a "care for girls" campaign nationwide in 2000 to promote equality between men and women.

The government has also offered cash incentives to girl-only families in the countryside.

The authorities said such programs will continue to fight discrimination against girls and to adopt more policies to ensure the healthy growth of girls.

The authorities also pledged to "firmly" continue the 33-year-long family planning policy, as the country is still facing huge challenges from growing population. The policy requires most urban couples to have only one child.

"Maintaining a low birth rate is the priority of the family planning during the next phase," the statement said, adding that the next four years is a "crucial" period.

The government has pledged to keep the mainland population under 1.36 billion by 2010 and under 1.45 billion by 2020.

"Over the coming decades, China's overall population will increase by eight to 10 million annually," bring unprecedented challenges to the country's social and economic development, the statement said.

"By the first half of the 21 century, China's overall population, working population and aging population will peak," noted the statement.

China currently has 1.3 billion people.