|China's relationship with governments such as Sudan comes in for criticism in the leaked cables [EPA]
The United States believes that China has "no morals" in its dealings with Africa, according to an assessment in a leaked diplomatic cable.
The cable quotes Johnnie Carson, the US assistant secretary of state for African affairs, describing China as a "pernicious economic competitor" whose investments prop up unsavoury regimes.
"China is a very aggressive and pernicious economic competitor with no morals. China is not in Africa for altruistic reasons," Carson said in a February meeting with oil executives in Nigeria.
"China is in Africa for China primarily," he said, according to a confidential cable written by the US consul-general in Lagos earlier this year.
Chinese investment in Africa has exploded in recent years, reaching a total of $9.3 billion by the end of 2009. Chinese state media say that more than 1600 businesses are investing in Africa in a range of industries, from mining to manufacuring.
But Beijing has come in for major criticism over its support for some governments on the continent. Many African leaders have praised Beijing for not lecturing them about human rights, something which Carson recognises as a problem.
"The United States will continue to push democracy and capitalism while Chinese authoritarian capitalism is politically challenging," Carson said.
Beijing pursues a "contrarian" approach by dealing with the "Mugabes and Bashirs of the world", he said, referring to the Zimbawean and Sudanese leaders respectively.
Carson said the US had "trip wires" in terms of China's presence in Africa.
"Is China developing a blue-water navy? Have they signed military base agreements? Are they training armies? Have they developed intelligence operations?" he said.
"Once these areas start developing, then the United States will start worrying," he said, though noting for the time being, Washington did not perceive China as a "military, security or intelligence threat".
China has not commented on any of the contents of the diplomatic cables, which were made public last month by the WikiLeaks whistleblower website.
The cable was one of dozens relating to Africa, revealing how US diplomats view the continent.
In another, the US ambassador to Kenya warns that corruption in country could trigger a wave of violence worse than that which engulfed the country following the 2007 election.
"Failure to implement significant reforms will greatly enhance prospects for a violent crisis in 2012 or before -- which might well prove much worse than the last post-election crisis," the cable says.
The documents also contain some less than flattering pen-portraits of African leaders. Thabo Mbeki, the former president of South Africa is described as a "thin-skinned" and "hypersensitive" leader who requires "deft handling".
In a cable sent by Ronald McMullen, the US ambassador to Eritrea, Isias Afwerki, the country's president, is said to be an "unhinged dictator" who is "cruel and defiant".
The ambassador recounts a conversation with a leading businessman in Asmara, the country's capital, in which Afwerki is described as "sick". McMullen says that Afwerki's government is "one bullet away from implosion", but notes that the regime is "very good at controlling nearly all aspects of Eritrean society."