US President Barack Obama has said he wants a "new model" for development during his first visit to Tanzania.
Mr Obama and his family were greeted by Tanzanian President Jakaya Kikwete and troupes of dancers as they arrived in the main city of Dar es Salaam.
In a speech on the last leg of his Africa tour, the US president said Tanzania had the potential to transform the region.
Trade was expected to top the agenda in his talks with business leaders.
Asked whether the US had done enough to help the continent, he said: "Ultimately the goal here is for Africa to build Africa for Africans.
"Our job is to be a partner in the process and Tanzania has been one of our best partners."
Mr Obama has been criticised for lacking a grand programme for Africa, and many Africans have been disappointed at what they see as his lack of engagement with the continent, despite his ancestry there.
The president said he wanted to move away from traditional forms of international development and work more closely with businesses in Africa.
"We are looking at a new model that's based not just on aid and assistance but on trade and partnership," he said.
"Increasingly what we want to do is use whatever monies that we're providing to build capacity."
Examples he gave included investment in health systems, food self-sufficiency and sustainable power sources.
During his first visit to Tanzania, Mr Obama will also visit an US-owned power plant following his announcement over the weekend of a multi-billion-dollar electricity initiative.
The $7bn (£4.6bn) five-year initiative is intended to double access to electricity in sub-Saharan Africa, in partnership with African countries and the private sector.
He made the announcement at South Africa's University of Cape Town after the US first family had visited Robben Island, the former jail where Nelson Mandela spent 18 years of his 27 years in captivity during his fight against the apartheid regime.
During his time in South Africa, the US leader did not visit Mr Mandela, who remains critically ill in hospital suffering from a lung infection, but he did met the Mandela family in private.
'Barack Obama Drive'
Correspondents say roads have been closed and security stepped up in Dar es Salaam for the US president's visit.
Hundreds of people lined the streets wearing T-shirts and sarongs bearing images of Mr Obama, in the warmest welcome he has received in his three-country visit to Africa, they say.
The crowds forced Mr Obama's motorcade to slow at times as it sped along a main road in the city that has been permanently renamed "Barack Obama Drive", in honour of America's first president of African descent, the Associated Press news agency reports.
"For development you need investments to utilise the huge potential that there is so that this huge potential can translate into incomes and jobs for our people and therefore development for our country," President Kikwete told the BBC's Newsday programme ahead of his arrival.
While in the country, Mr Obama is due to launch a programme helping Africa's eastern nations of Burundi, Kenya, Rwanda, Tanzania and Uganda trade both with each other and with the US.
He also signed an executive order aimed at preventing wildlife trafficking, particularly the sale of rhinoceros horns and elephant tusks.
On Tuesday, Mr Obama will lay a wreath at a memorial outside the US embassy in Dar es Salaam, in honour of 11 people killed in a bombing by al-Qaeda in 1998.
His wife Michelle Obama is expected to take part in African First Ladies Summit organised by the George W Bush Institute and hosted by her predecessor Laura Bush.
Mr Obama's second tour to sub-Saharan Africa since becoming president began in Senegal where he called on African governments to give gay people equal rights by decriminalising homosexual acts.
The US president has excluded from his itinerary Kenya, where his father was born, and Nigeria, Africa's biggest oil producer which has been hit by an Islamist insurgency.