BEIJING - China is still looking at evidence that male circumcision can play an important role in fighting the spread of AIDS and is not currently considering such a campaign, a senior health official said on Friday.

Late last year, researchers in the United States and Africa said that circumcising men cut their risk of being infected with the AIDS virus in half, and could prevent hundreds of thousands or even millions of new infections globally.

Circumcising men worked so well that the researchers stopped two large clinical trials in Kenya and Uganda to announce the results, although they cautioned that the procedure does not make men immune to the virus.

"We have already noticed these reports from Africa," Ru Xiaomei, deputy director general of China's National Population and Family Planning Commission, told Reuters in an interview.

"But the AIDS situation in China has not yet reached such a large scale (as in Africa)," she said.

China's family planning authorities, with decades of experience at promoting contraception, are increasingly being drafted into the country's fight against AIDS.

In China, which has an estimated 650,000 people living with HIV, the virus is gradually spreading from high-risk groups like intravenous drug users to the general population via sex.

"I'm not yet totally certain about the evidence for circumcision," Ru said. "We should exercise caution."

Circumcision rates are low in China compared to Asian countries like South Korea or Japan, where the foreskin is often removed at birth for hygiene reasons, or Muslims in countries like Indonesia who practice it for religious reasons.

China's Muslim minority, concentrated in the far western region of Xinjiang, likewise circumcise their male children, normally as they reach puberty.

That could perhaps mean a wider campaign in China would run into cultural problems and opposition from the non-Muslim majority, said Ru, a medical doctor by training,

"There's a problem with cost too," she added, in a country with the world's largest population - 1.3 billion people. "It would be a big deal. It's much more reasonable to get people to use condoms."

A US National Institutes of Health study in Kisumu, Kenya, involving 2,784 men aged 18 to 24 showed a 53 percent reduction of HIV infections in circumcised men compared to uncircumcised men. A parallel study involving 4,996 men aged 15 to 49 in Rakai, Uganda, showed circumcised men were 48 percent less likely than uncircumcised men to become infected.

Experts say the reduced HIV risk may be because cells on the inside of the foreskin, the part of the penis cut off in circumcision, are particularly susceptible to HIV infection. HIV also may survive better in a warm, wet environment like that found beneath a foreskin.