WASHINGTON (AFP) - The United States on Monday said it had a "positive agenda" for Africa to help lift its nations out of poverty as Washington watched a trip to the continent by new Chinese leader Xi Jinping.

In a keynote speech on Monday, Xi addressed leaders in Tanzania as "my dear friends" and spoke of Beijing's "sincere friendship" with Africa, saying its trade with China reached US$200 billion (S$248.7 billion) in 2012.

China plans to "intensify, not weaken" its relationship with the continent, Mr Xi said, noting a commitment to provide a US$20 billion credit line to African nations over the next two years.

Asked whether Washington saw itself in competition with Beijing for ties in Africa, State Department acting deputy spokesman Patrick Ventrell said "our relationship is not necessarily defined by competition alone." "We may have divergent interests in various spheres in Africa, but we continue to promote our positive agenda," he told reporters.

"We want partnerships with all of these countries, and we're looking to promote democracy and sustainable development," as well as "a new way forward for some of these countries to lift themselves out of poverty and to treat disease." Mr Xi is on his first foreign trip since being anointed president 11 days ago and was in Russia last week. Washington has had awkward ties with both Beijing and Moscow.

But State Department spokesman Victoria Nuland said last week Washington was "completely relaxed" about Mr Xi's visit to Russia, since he had already visited the United States last year before he was officially appointed.