Obama wraps up Africa tour

Obama was joined by his Republican predecessor on Tuesday for the final hours of his eight-day visit to the continent.

Flanked by their wives, the two men observed a minute's silence at a wreath laying ceremony at the site of the 1998 bombing in Tanzania's capital.

In August of that year al Qaeda-linked militants carried out twin attacks at US embassies in Dar es Salaam and Kenya's capital, Nairobi, killing more than 200 people. Some 11 Tanzanians were killed and 85 Americans and Tanzanians were wounded in the Dar es Salaam attack.

The US presidents' paths had crossed unexpectedly in the Tanzanian capital, where the Bushes are hosting a summit promoting the role of African first ladies.

Obama and his wife Michelle meanwhile were wrapping up their three-stop Africa tour, which was designed to focus on expanding US-Africa trade ties, before departing back to the United States.

Power pledge

The president's two-day trip to Tanzania also took him to a US-funded power plant near the capital. The visit followed his pledge over the weekend to invest $7 billion (5.34 billion euros), alongside another $9 million from the private sector, in expanding electricity networks on the continent.

"One of the biggest hurdles to Africa's economic development is the fact that nearly 70 percent of Africans lack access to electricity," Obama said alongside Tanzania's President Jakaya Kikwete.

"I believe that the purpose of development should be to build capacity and to help other countries actually to stand on their own feet."

"Instead of perpetual aid, development has to fuel investment and economic growth so that assistance is no longer necessary."

Obama also demonstrated a soccer ball, developed by two Harvard graduates, which produces energy when kicked around. "Sockket" has a pendulum-like mechanism that creates and stores kinetic energy during play. It is designed to bring energy to communities off the power grid.

Paying tribute to Mandela

Obama arrived in Tanzania from South Africa on Monday. There he paid tribute to the anti-apartheid leader Nelson Mandela, describing him as a "personal inspiration."

He visited Mandela's former prison cell on Robben Island, where the ailing leader spent 18 of his 27 years behind bars.

He was unable to visit the former South African president, however, as he remains critically ill in a Pretoria hospital. Mandela has been suffering from a chronic lung infection for three weeks.

ccp/kms (AP, dpa)