JOHANNESBURG -- Aids will claim another 68 million lives by 2020 and make sustainable development a pipe-dream unless the epidemic is curbed, the United Nations said in a report released Thursday on the sidelines of the Earth Summit, AFP reported.

"AIDS depletes human resources, saps productive capacity and deepens poverty and hardship," says the UNAIDS agency report on the impact of AIDS on agriculture, health and education. "In two decades, it has killed more than 20 million people. By 2020, another 68 million face premature death in the 45 most affected countries ... the challenge is to act now."

Releasing the document, UNAIDS Drector Peter Piot said that at this rate the HIV epidemic would make it impossible to achieve the summit's aims of eradicating poverty while protecting the planet's resources for future generations.

"In many parts of the world, one can forget about sustainable development if the AIDS epidemic is not brought under control," he told reporters. "If people who are supposed to bring about sustainable development are not alive, are not healthy, it will not happen."

The report says the only answer is to prevent further HIV infection and to treat the 40 million people who already carry the virus.

"Prevention works. Treatment and care save lives. The world knows what it takes to set effective responses in place everywhere they are needed." Piot said it was vital that the final declaration of the 10-day summit, which opened in Johannesburg on Monday, recognize that AIDS is as a "cross-cutting issue for sustainable development" and does not only deal with the disease "under the health heading."

He said he was shocked that it was left of the initial agenda for the summit.

"We managed to have it added at the preparatory meeting in Bali.

It was not that difficult, it was just as if they had forgotten," he said.