Hillary Clinton told the International Aids conference yesterday that the United States remains determined to eradicate the disease even as the search for a vaccine and a cure continues.
But warnings were sounded that progress made so far could be reversed by a fall-off in funding caused by the economic slowdown.
"The US is committed and will remain committed to creating an Aids-free generation: we will not back down," the US Secretary of State told delegates at the start of the five-day meeting.
Aware of the concern that money for research and treatment around the world is at risk of drying up, she added: "We will fight for the resources necessary to achieve this historic milestone."
Anthony Fauci, the head of Aids research at the National Institutes of Health, said later: "Obviously when there are constrained resources there is some impact on your ability to implement." One solution, he said, was to "bring in more countries that have not yet participated very robustly". He noted that Japan, Germany and Saudi Arabia had recently stepped up contributions.
Met both by loud cheers and sporadic heckling, Clinton explained that, while there is still no vaccine to prevent HIV infection or cure for Aids, the development of anti-retroviral drugs means that the world can now aim to stop HIV becoming Aids in patients everywhere and thereby also stem the pandemic's spread.
An "Aids-free generation", her declared goal, means a world, she said, where virtually no child will be born with the HIV virus, where "as children and teenagers become adults, they will be at a significantly lower risk of becoming infected than they would be today no matter where they are living", and where anyone who has the virus will have full access to drugs that keep them healthy and will stop them from transmitting the disease.
Yet some will remain sceptical of Clinton's oratory. Under pressure to deal with the deficit, President Barack Obama has proposed cuts in the largest US programme for Aids in the 2013 budget.
"The US Government's commitment to turn around the epidemic is good news," Sharonann Lynch of Doctors without Borders said. "But all donors need to reverse their [freeze in] funding for global HIV/Aids so we can reach the one in two people in urgent need of treatment who still do not have access."
Michel Sidibe, the chief of UNAids, reminded the conference that, while the world spent US$16.8 billion ($21.2 billion) fighting Aids in poor countries, this was still US$7 billion a year short of the amount needed to double the 8 million people getting life-saving drugs by 2015.
"This gap is killing people. My friends, the end of Aids is not free. It is not too expensive. It is priceless."