It's Saturday night at Makerere University and the abstinence party is in full swing around the campus swimming pool.

More than a thousand young men and women sway to the reggae sounds of local musicians and singers. Some dance. A few flirt. But the sexual tension ends there. At night's end, hundreds sign pledge cards vowing to shun sex until marriage.

"We're waiting," said Sylvia Moos Muzaale, 25, a smiling library sciences major seated next to her boyfriend of three years. He gives a shrug that suggests he's not entirely happy with the decision.

The weekly bash is part of a burgeoning anti-AIDS campaign in this East African nation, where virginity is fast becoming a national obsession.

Billboards with the logo "Abstinence: You Can!" dot the capital's streets. "Somewhere out there," one giant poster reads, "she's keeping herself for you." A member of parliament is offering scholarships for young women who undergo gynecological exams to prove their chastity.

Now AIDS activists are warning that the focus on abstinence, and a related backlash against condoms, is threatening Uganda's progress in combating AIDS. Prevalence rates here have dropped from 18 percent in 1992 to 7 percent today in a country where 1 million people have died from the disease and another million are infected.

"Abstinence is fine for some but not for everyone," said Edith Mukisa, who heads Kampala's Naguru Teenage Center. "What about people that don't marry? What about poverty, which forces many young people to take sugar daddies or sugar mommies for money? I'm afraid we're going to have another boom in the HIV rate."

Uganda's AIDS prevention campaign, launched in the late 1980s and considered one of the world's most successful, has fractured over its much-touted A-B-C strategy, which focuses on abstinence, being faithful and condoms.

Complaining that the A-B part of the message was getting short shrift, religious groups and some politicians, with support from churches and conservative groups in United States, declared war on the C camp.

"People act as if condoms are more important than food," said Martin Ssempa, host of the campus abstinence parties and founder of Makerere Community Church, which preaches chastity to students. Ssempa, a pastor, said he believed condoms encourage promiscuity and that condom promotion went too far, in such areas as explicit how-to demonstrations in schools.

"I'm not anti-condom," Ssempa said, although he acknowledged burning a batch on campus last year. "It's a moral issue. I believe in quiet promotion of condoms to certain groups."

Other critics have suggested that condoms cause cancer or have holes that allow the human immunodeficiency virus, or HIV, to permeate. Some even claimed condoms were secretly infected with HIV by the United States to spread the disease in Africa.

President Yoweri Museveni, who relied heavily on condom distribution in the past, shocked many by saying recently that condoms were "not the ultimate solution." His evangelical-leaning wife, Janet, who wants a national census to determine how many young people have had sex, suggested that condom promoters were racist because they believed "Africans cannot control their sexual drives."

Their statements led to criticism by other political leaders who declared condoms "un-African" and suitable only for sex workers, truck drivers and those already infected with HIV.

"Because of the stigmatization, those of us arguing for condoms were suddenly looked at as people who are immoral," said Beatrice Were, an AIDS activist here.

For young people, the debate has been particularly dangerous, some experts say.

"The more confused young people are, the more they put themselves at risk," said Mukisa, of Kampala's teenage center. "It's an issue of mixed messages." She said she sees an increase in homosexuality, oral sex and anal sex among young people who tell her, in anonymous surveys, that they've turned to such practices in an effort to "stay virgins."

It's too early to determine the impact on AIDS prevalence rates. The state Health Ministry reported this year that a new study found that the national rate was 7 percent, up from the most recent estimate of 6.2 percent. Officials attributed the increase to differences in data-collection methods, not changes in behavior.

Many AIDS officials blame the abstinence push on pressure from U.S. conservative groups, such as the Heritage Foundation and Focus on the Family, and on the Bush administration program called the President's Emergency Plan for AIDS Relief, or PEPFAR.

The five-year, $15 billion program has dramatically increased U.S. funding for AIDS work in Africa, but it includes a hefty earmark for programs that deal exclusively with abstinence and faithfulness. Two-thirds of its AIDS prevention budget must be spent on the A-B part of A-B-C.

One casualty is condom-distributor Population Services International, which lost its funding recently after being attacked by Ssempa and the U.S.-based organization Focus on the Family.

"The condom crisis in Uganda is being driven and exacerbated by PEPFAR and by the extreme policies that the administration in the United States is now pursuing in the emphasis on abstinence," said Stephen Lewis, former Canadian ambassador to the United Nations.

U.S. officials insist they have not interfered in Uganda's AIDS debate and noted that the program's funding for abstinence is part of a massive increase in overall aid. U.S. AIDS assistance in Uganda is about $150 million a year, more than the total spent between 1986 and 2001.

"There is no grand conspiracy where the U.S. government is convincing Ugandans not to promote condoms," said William Fitzgerald, deputy chief of mission in Uganda and head of the program.