The Clinton Foundation helps provide treatment for Aids patients
Former US President Bill Clinton has called for an increase in funding to keep down the cost of drugs for people with HIV.
Mr Clinton told a world Aids conference in Mexico that a 50% rise was needed in the next two years just to keep pace with expanding drug programmes.
Figures released ahead of the meeting show the number of people with HIV worldwide has decreased slightly.
However, infection rates are still rising in some countries.
Across the world 33 million people are affected by the syndrome.
"Aids is a very big dragon. The mythological dragon was slain by Saint George, the original knight in shining armour, but this dragon must be slain by millions and millions of foot soldiers," Mr Clinton told the conference.
A crowd of demonstrators holding banners calling for housing for people with HIV walked in front of the podium during his speech.
Mr Clinton used the moment to talk about how rising oil, food prices and the mortgage crisis had made the lives of people with HIV even more difficult.
There was "no silver bullet" to rid the world of the disease, he said.
"We know there is so much yet to be done: to expand prevention, treatment and care, to strengthen undeveloped health systems," he added.
The six-day conference was preceded by an awareness march, a photo exhibition and other events.
Campaigners call for universal access to anti-retroviral treatment
About 20,000 scientists, government officials and campaigners are in Mexico City for the event.
They used to separate out my plate, my spoon, my cup, fearing they would catch Aids
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