US President George W Bush on Wednesday called for a global fight against HIV/AIDS.

"HIV/AIDS is the greatest health crisis of our time. Its defeat requires the cooperation of the entire global community," Bush said in a message on the occasion of World AIDS Day.

He said to defeat the pandemic, "we also must discover new treatments and cures.

"My administration also supports efforts to encourage testing because in the United States alone, one-quarter of those infected with HIV each year do not know that they are infected.

"And, because abstinence is the only sure way to avoid sexually transmitted diseases, my administration has more than tripled funding for abstinence-only programmes since taking office," he said.

He said his administration had made "turning the tide" against HIV/AIDS a priority.

"This year, we also recognise the challenges HIV/AIDS poses to women. Through the 'Emergency Plan', the United States supports drug therapy and counselling to prevent mother-to-child transmission of HIV/AIDS," he said.

The US government had last year earmarked nearly $15 billion over a five-year period for the 'Emergency Plan for AIDS Relief' he added.