The United States is committed to the goal of an AIDS-free generation and will step up its efforts to stem the world pandemic, Secretary of State Hillary Clinton told a global conference Monday.

"The United States is committed and will remain committed to achieving an AIDS-free generation. We will not back off, we will not back down," Clinton told the International AIDS Conference meeting in Washington.

"We will fight for the resources necessary to achieve this historic milestone," she added, dismissing criticism that the United States was not serious in its bid to fight the 30-year AIDS/HIV pandemic.

The conference, which opened Sunday, is the world's largest gathering on HIV/AIDS and is expected to draw 25,000 people, including politicians, scientists, celebrities and activists.

Clinton said the world should soon be able to "actually imagine a time when we will no longer be afflicted by this terrible epidemic and the great cost and suffering it has imposed for far too long."

The US top diplomat unveiled new US funding efforts to support male circumcision in South Africa, help HIV-pregnant women get access to treatment to stop them infecting their babies, as well as research on intervention.

"This is a fight we can win. We have already come so far, too far to stop now," she said, drawing loud applause and cheers from the audience.

Some 34 million people in the world are living with HIV, according to the latest UNAIDS report. However, about one in five people are not aware of their status and are most at risk of spreading the disease.

Clinton acknowledged that without a vaccine or a cure for HIV it would remain in the world, but insisted that "the disease that HIV causes need not be with us."

In an AIDS-free generation, virtually no child would be born with the virus, teenagers growing up would be at a lower risk of becoming infected, and should they develop HIV they would get the treatment needed to stop them developing AIDS and passing it on, she said.

Held every two years, the conference has returned to the United States for the first time since 1990, after being kept away by laws that barred people with HIV from traveling to the country.