US President George W Bush has arrived in Benin at the start of his first presidential tour of Africa since 2003.
After talks with President Thomas Boni Yayi, he renewed a US pledge to supply mosquito nets to tackle malaria.
And he called for a power-sharing agreement to end Kenya's violence following disputed presidential polls.
He said he would highlight African success stories during his six-day, five-nation visit, even though he remained committed to ending turmoil.
Democratic reform, economic and military assistance, and the fight against HIV/Aids are expected to be raised.
The US president also wants to allay concerns about a new military command he wants to base in Africa.
After the Benin talks, Mr Bush called for urgent action over the "genocide" in Sudan's region of Darfur, where at least 200,000 people have died and two million been displaced in a five-year conflict.
PRESIDENT BUSH'S ITINERARY
Benin - Cotonou: arrival ceremony, meets president
Tanzania - Dar-es-Salaam: meets president, tours hospital; Arusha: tours hospital, textile mill and girls' school
Rwanda - Kigali: meets president, visits genocide memorial
Ghana - Accra: meets president, state dinner
Liberia - Monrovia: meets president, visits university
In a BBC interview prior to his tour, the US president defended his Darfur stance, saying he had not wanted to send US troops into another Muslim country.
He said the US had instead imposed sanctions on Sudanese leaders and companies, and that he would remind the president of China "that he can do more to relieve the suffering in Darfur".
For a president whose foreign policy has been defined by Iraq this visit is an opportunity to show the more compassionate side of his legacy, says the BBC's Laura Trevelyan who is travelling with Mr Bush.
America has spent $15bn (£7.5bn) fighting Aids overseas since 2003, and Mr Bush has recently asked Congress to double that amount.
More than one million people in sub-Saharan Africa have life-saving anti-retroviral drugs thanks to the policy.
However the policy has been criticised by some for focusing on encouraging people not to have sex in order to stop the spread of Aids - unrealistic critics say.
The US leader will visit hospitals, schools and businesses, hoping to show how US investment in health and development programmes has made a real difference to Africans.
In Benin, Mr Yayi presented his guest with the Grand Cross of the Order of Benin.
Receiving the "great honour", the US leader went on to say highlight the American people's "great compassion" in giving aid to Benin.
"I stand here by your side as a friend, a believer in your vision and a partner in your willingness to confront the disease and poverty that affect mankind," he said.
"We would not be standing here if you and your government was not committed to your people."
However, international aid agencies have said US trade policy in Africa may undermine struggling African economies.
Benin relies on cotton production, for instance - but cannot compete with US cotton because of the large subsidies paid to US farmers.
Analysts say Mr Bush may also be concerned with countering the influence of China - which has been doing billions of dollars worth of trade deals in Africa.
Also likely to be on the agenda is the location of a new American military command headquarters, known as Africom, whose primary role, according to Mr Bush, will be to work with African militaries to deal with trafficking or terror.
So far, Liberia is the only nation to have offered to host the US base. There are already some 1,700 US troops in Djibouti.
Correspondents say the idea of an increased US military presence makes regional powers such as South Africa and Nigeria wary.