On a low-profile visit to Rwanda recently, Gates offered the funds to set up the Center for Training and Operation Research to serve five nations: Rwanda, Uganda, Burundi, Tanzania and the Democratic Republic of Congo.

?Such support from well-wishers will go a long way in helping developing countries achieve much in the war against the scourge,? Dr Agnes Binagwaho, executive secretary of Rwanda's National Aids Commission, said late on Wednesday. Sub-Saharan Africa remains the region hardest-hit by AIDS, with about 25 million people infected. Binagwaho told Reuters 3 percent of HIV.

The ultra-modern facility will be run from Kigali by international experts under the coordination of Rwanda's AIDS Treatment and Research Center, the official added.

Gates, the world's wealthiest man and a major international philanthropist, was in Africa on a holiday with his wife Melinda and children, Rwandan officials said.

The Bill & Melinda Gates Foundation announced grants worth $287 million to create an international network of 16 labs to try new approaches for making a vaccine against AIDS.