President George W. Bush has praised Ugandan attempts to tackle the Aids virus during his four-hour visit there.
Bush is spending five days on a lightning tour of the continent
Speaking before departing for Nigeria, the fifth and final nation on his tour of the continent, he also underlined his government's commitment to the battle against Aids in Africa saying: "When history called, we responded".
Uganda is the only African country which has successfully managed to reverse the tide of Aids infections and Mr Bush sees it as a model for his own $15bn Aids initiative on the continent.
During a meeting with Ugandan President Yoweri Museveni, the US leader said: "You have shown the world what is possible in terms of reducing infection rates".
Mr Bush also visited an Aids support organisation and met Aids sufferers who were to ask him about better access to life-saving anti-retroviral drugs.
Most of the Ugandans who need the drugs cannot afford to pay for them - even with the new generic drugs available on the market.
Uganda has successfully fought Aids with an aggressive public information campaign after the epidemic slashed life expectancy from 48 years to 38 during the 1990s.
In the early 1990s, the rate of HIV infection in some urban areas was as high as 30%, but today just 6% of the total population now carries the virus.
Mr Bush again repeated in Uganda his pledge to spend $15bn on fighting Aids across Africa over the next five years.
But back in Washington, a House of Representatives subcommittee in charge of foreign aid has allocated just $2bn to fight global Aids in the coming fiscal year instead of the expected $3bn.
Jim Kolbe, chairman of the subcommittee, predicted Congress would still live up to its promise to spend $15bn over five years.
But he said that spending $3bn in the first year, as Mr Bush had originally proposed, was unrealistic when the programme was just getting off the ground.
Officials in the US legislature point out that the $15bn figure given by Mr Bush was meant to be a ceiling or a guideline - and did not necessarily represent the total amount of allotted funds.
The trip is giving President Bush a close-up view of some of the continent's protracted crises, and he has been dogged by the question of whether to send US peacekeepers to Liberia.
On Wednesday, Mr Bush suggested that US assistance to Liberia might consist mostly of advisers and trainers to avoid stretching American forces too thinly around the globe.
He said US money had helped pay for the training of seven battalions of African peacekeepers.
He said it was a "sensible policy" to help the Africans help themselves "so that we never do get overextended".
Nigerian Vice President Atiku Abubakar, however, has told the BBC's Network Africa that he expects the United States to provide forces for Liberia alongside Senegal, Ghana and Nigeria
He said Nigeria was preparing to send two battalions of troops to Liberia within the next two weeks.
Mr Abubakar said that other issues to be discussed when Mr Bush arrives in Nigeria later on Friday would be oil and co-operation on economic and military matters.