WASHINGTON, United States (AFP) — When Barack Obama welcomed African leaders to Washington in 2014, many viewed the summit as historic, not just due to the United States president's background but for the pledges to make the partnership deeper and such events routine.

The sequel took eight years — the equivalent of two presidential terms — but on Tuesday, Joe Biden will host a second US-Africa summit.

Since 2014, China — viewed by Washington as its main long-term challenger — has consistently outpaced the US as the largest investor in Africa and Russia has increasingly flexed its muscle, sending mercenaries to hotspots and trying to rally opinion to blunt Western pressure over Ukraine.

Biden's three-day summit will feature announcements of new US investment and highlight food security — worsened by the invasion of Ukraine — but, unlike China, also focus on values such as democracy and good governance, as well as fighting climate change.

But the biggest message from Biden, a lover of backslapping face-to-face diplomacy, will be that the US cares.

Since defeating Donald Trump, who made no secret of his lack of interest in Africa, Biden has thrown his support behind an African seat on the Security Council and at the Washington summit will call for the African Union to formally join the Group of 20 major economies, an aide said.

African leaders have already been holding summits every three years with China and also have regular meetings with several US allies — France, Britain, Japan and the European Union.