US Secretary of State Rex Tillerson says African countries should weigh Chinese loans carefully, while adding that Washington is not trying to keep Chinese investment away from the continent.
Tillerson, a former Exxon chief executive, is seeking to bolster security alliances on a continent increasingly turning to Beijing for aid and trade.
The top US diplomat may also seek to smooth relations after US President Trump reportedly dismissed some African nations as "shithole countries" in January. Trump later denied making the comment.
"We are not in any way attempting to keep Chinese dollars from Africa," Tillerson told a news conference in the Ethiopian capital during his first diplomatic trip to the continent. "(But) it is important that African countries carefully consider the terms of those agreements and not forfeit their sovereignty."
Though the United States is the leading donor of humanitarian aid to Africa, China surpassed the US to become Africa's largest trading partner in 2009.
Beijing has pumped billions into infrastructure projects, though critics say there is often little upside for local economies because Chinese firms and labour build the roads and rails.
Tillerson took that line on Thursday, saying that Chinese investments "do not bring significant job creation locally" and criticised how Beijing structures loans to African government.
Russian foreign minister Sergei Lavrov, visiting Zimbabwe on Thursday, told reporters he did not think it was appropriate for Tillerson to criticise China's relationship with African countries.
"It was not appropriate to criticise the relations of his hosts when he was a guest there with another country," he said.
