WASHINGTON, Dec 13 (AFP) - The United States warned on Tuesday (Dec 13) that China and Russia were destabilising Africa with their growing inroads as it rolled out the red carpet to the continent's leaders and pledged billions of dollars in support.

Forty-nine African leaders flew into the Washington cold for the first continent-wide summit with the United States in eight years as President Joe Biden seeks to use personal diplomacy to win back influence.

Defense Secretary Lloyd Austin, at a panel with several African presidents at the start of the three-day summit, charged that US rivals had a different approach.

Austin said China was expanding its footprint in Africa "on a daily basis" through its growing economic influence.

"The troubling piece there is they're not always transparent in terms of what they're doing and that creates problems that will be eventually destabilising, if they're not already," Austin said.

Russia is "continuing to peddle cheap weapons" and deploying "mercenaries across the continent," he added.

"And that is destabilising as well."

But the Biden administration has been careful not to present Africans with an us-or-them choice, believing it is futile to try to turn the tide on China's massive infrastructure spending.