The United States Secretary of Commerce, William Daley, who is in Kenya, has urged African countries to work with transparency and openness in order to encourage foreign investment.

Mr Daley warned about the problem of corruption, describing it as a crime committed against society, which diverted resources that could be used to improve health, education and housing.

He also stressed the need for infrastructural improvements to make it easier for companies to get their products to market.

It's Mr Daley's third visit to Africa this year, and correspondents say the aim is to emphasise America's commitment to expanding commercial ties with Africa.