Hillary Clinton on 11 Day Tour of Africa

China surpassed the U.S. as Africa's largest trading partner three years ago but the U.S. is expanding its military presence on the continent.

Hillary Clinton, the US secretary of state, has started an 11-day tour of Africa by contrasting America's commitment to democracy and human rights with rival powers' focus on exploiting resources.

Although Clinton did not mention any country by name, her remarks will be widely interpreted as a swipe at China, which eclipsed the US as Africa's biggest trading partner three years ago.