South Africa has announced a five-year plan to try to combat HIV/Aids, with a promise to cut infection rates by half.
The government action plan is seen as a message of hope
More than 1,000 South Africans die of Aids-related illnesses every day, but many more are still being infected.
Reversing its previous advice of a diet of garlic and beetroot as a treatment, the government has formed an alliance with civic groups campaigning on Aids.
Activists have welcomed the new plan, but warned it was still vague and lacked specific commitments.
The broad framework document, announced by Deputy President Phumzile Mlambo-Ngcuka, marks a significant change in government policy.
Seen as a message of hope, Ms Mlambo-Ngcuka said much progress had been made in building partnerships with civil groups and together they could turn the tide of the pandemic.
"We were united when we fought apartheid and we defeated it. So we are used to challenges but determination is a crucial element," she said.
Residents crowded inside the stadium to hear the announcement
Speaking at a sports stadium near the eastern town of Nelspruit, she said the government wanted to halve the number of infections by 2011, targeting in particular young people aged 15 to 24.
Plans to extend treatment to 80% of those who are HIV positive were also outlined. At present five and a half million people in the country are infected.
'Silence is death'
The BBC's Southern Africa correspondent Peter Biles says although many details of the new policy have still to be spelt out, after years of confusion and ambiguity the South African government finally has a clear policy on HIV/Aids.
The country's former policy, which emphasised diet over the use of antiretroviral (ARV) treatment, was widely criticised.
The lobby group, Treatment Action Campaign, which had been one of the government's harshest critics is encouraged by the dramatic turn of events.
"Government is saying at the highest level, apart perhaps from the president, that HIV is an emergency, that it's a priority, that we need to scale up our treatment services for people, that we need to prevent HIV infections.
"That type of language is a language on which it's possible to work with government," said spokesman Mark Hayward.
Earlier, in a speech to mark World Aids Day, UN Secretary General Kofi Annan urged more frank and open discussion of HIV/Aids.
All politicians had to consider themselves personally accountable for stopping the spread of the disease, Mr Annan said, as did every individual.
Last week, deputy Health Minister Nozizwe Madlala-Routledge publicly took an Aids test in what correspondents say is another sign of the government's greater commitment to fighting the crisis.
She is the most senior ANC member of government to take a test and told the BBC she hoped it would encourage others to follow suit.
Figures recently released by the UN reveal that in terms of numbers, India is now facing the most severe HIV/Aids burden of any country in the world, with 5.7 million people infected.
Former US President Bill Clinton said in a BBC interview that India was the new epicentre of global infection, and the challenge to control the spread of the virus there was "breathtaking".
Elsewhere, countries marked World Aids Day with a series of events, including:
- The broadcast of radio and television messages in 25 countries across Africa aimed at preventing the spread of the disease among young people
- A march by Indonesian activists through the streets of the capital, Jakarta, demanding an end to the stigma attached to HIV/Aids
- A plan by activists in Thailand to create the world's "longest condom chain", a ribbon of 25,000 condoms stretching through a Bangkok park
- An announcement by Australian Foreign Minister Alexander Downer for an extra US$170m (£83m) to help its Asia-Pacific neighbours tackle the HIV/Aids epidemic