The United States on Wednesday rejected a call at the International AIDS Conference for a $1 billion contribution next year to the global fund that has become the centerpiece of U.N. efforts against the disease.

“It’s not going to happen,” U.S. AIDS coordinator Randall Tobias said in an interview, noting that Washington already is by far the world’s largest donor to the cause.

Tobias’ comments were in response to a request Tuesday by U.N. Secretary-General Kofi Annan, who said he hoped the United States would give $1 billion for 2005 alone to the Global Fund, which is far short of its $3.6 billion budget.

The United States is carrying out a $15 billion, five-year Emergency Plan for AIDS Relief, mainly directed toward 14 countries in Africa and the Caribbean, plus Vietnam. Critics say the United States should instead give much of that money to the Global Fund, which reaches 128 countries.

They also say the U.S. money comes with strings attached that can set back efforts to curb the spread of the HIV - which infected 5 million people last year alone - and that the U.N.-sponsored fund best suits the needs of sufferers.

The U.S. money goes to countries that support Bush’s abstinence-first policy, and it currently can only buy brand-name drugs, usually American, shutting out cheaper generic versions made by developing countries.

Tobias urged detractors to stop arguing with Washington over condoms and drug patents and join its war on the pandemic, which has claimed 20 million lives and left another 38 million infected worldwide since 1986, most of them in Africa.

There has been furious criticism at the AIDS conference of U.S. policies such as its insistence on abstinence - rather than condoms - as a primary way of battling HIV; its trade policies; and its funding methods. The conference is the biggest gathering ever of AIDS scientists, activists, policy-makers and HIV-infected people.

Critics say a vow of abstinence is difficult to maintain and, when broken, can lead to unprotected sex, raising the risk of HIV infection that could effectively be blocked by a condom.

Tobias was jeered by protesters chanting, “He’s lying! People dying!” when he was about to defend U.S. policies in a speech Wednesday.

One activist, Mark Milano, 48, of New York, said that when it comes to fighting AIDS, “every step of the way, the U.S. government is not doing what it should be doing.”

“It’s not working with other countries. It’s going at it alone, like it did with Iraq,” he said.

Tobias said that while the United States is not against condoms, an abstinence campaign in Uganda shows that the contraceptives are not the only solution.

“At this point, perhaps the most critical mistake we can make is to allow this pandemic to divide us,” he said.

He pointed out that the United States will this year spend $2.4 billion, nearly twice as much to fight AIDS as the rest of the world’s donor governments combined.

With such massive spending, there’s no need to contribute additional money to the U.N.-sponsored Global Fund to Fight AIDS, Tuberculosis and Malaria, he said. The $200 million that President Bush already plans to contribute next year is sufficient, he said told reporters.

Stephen Lewis, the United Nations’ special envoy on HIV/AIDS to Africa, said he disagreed “profoundly” and that the Tobias stance showed “an inability to recognize the way the world most effectively works.”

The Global Fund allows generic drugs, costing as little as $150 per person per year, while those approved under the U.S. plan typically cost $700, said Joia Mukherjee, medical director of Partners in Health, which treats the poor in Haiti.

“The last thing I want to worry about is which bottle this stuff is coming out of,” she said.

Tobias said Washington insists on name-brand drugs because their quality has been tested by the U.S. Food and Drug Administration. However, U.S. AIDS programs have been ready to use generic drugs and copies, provided they are approved by the FDA, Tobias said.

No generic drug maker has come forward to seek FDA approval, and Tobias said the United States would not accept the World Health Organization’s certification, describing the WHO’s drug approval process as “not transparent.”

Wednesday’s agenda featured sessions on the growing infection rates among youth and women.

Experts say nearly half of all people with HIV are women, and their infection rates in many regions are climbing much faster than men’s.

Raoul Fransen of the Netherlands told a plenary session the abstinence-first approach did him no good, and that after learning he was HIV positive at age 15, he thought he would never have sex again, for fear of infecting others.

“It took a while before I was ready to experience intimacy again,” said Fransen, 26.