Men having sex with other men accounted for 73.5 percent of the total population infected with HIV or AIDS in Beijing, the city's health department reported on Thursday.

"It is difficult for this group to quit high-risk same-sex behavior. Therefore factors leading to such a disease will continue to exist," said Gao Xiaojun, an official from Beijing Municipal Commission of Health and Family Planning.

In the past year, the number of patients infected with HIV and AIDS in Beijing reached 3,452.

Since 1985, there have been 18,635 reported cases of HIV/AIDS. The proportion of unreported cases is high, said Gao, stating that 95.3 percent of infections were caused by sexual transmission.

Official data from several domestic cities also showed the proportion of same-sex transmissions of HIV infection has gradually increased in recent years.

The Disease Control and Prevention Center in Xiamen, Fujian province said on Thursday that same-sex transmission contributed to 57.7 percent of the city's new HIV or AIDS cases in the first 10 months of this year.

Newly-reported cases in Binzhou, Shandong province, which has a low HIV infection rate, have risen and male homosexual transmission accounted for about 70 percent, Binzhou Daily reported on Thursday.