US Secretary of State Hillary Clinton has concluded an 11-day tour of Africa in which she promoted a new US strategy for the continent.

The visit also stoked international debate about whether the US and China, the world's two biggest economies, are competing for resources in Africa.

Clinton's remarks during the trip, although not mentioning any country by name, were widely interpreted by analysts and media to be targeting China and lobbying African leaders to cooperate with the US, which was replaced by China three years ago as Africa's biggest trading partner.