China has invited the US to co-operate in financing and building infrastructure in Africa and other parts of the developing world, an unprecedented proposal that has potentially sweeping implications for the future of international development aid.

Chinese officials first approached Washington last year to discuss working together on a $12bn dam project in the Democratic Republic of Congo, US officials said, but the talks gathered momentum at the annual China-US summit in July in Beijing.

The putative partnership is challenging: a bid for what could be the world’s largest hydropower complex, in one of the world’s least developed countries. While the World Bank has funded a report to evaluate the project, proposals for the Inga-3 dam have been discussed for years without resolution.