Biden commits 'historic' $4bn to World Bank fund supporting poorest nations

US President Joe Biden announced a "historic" $4 billion pledge for a World Bank fund that helps the world’s poorest countries, the White House said Monday, before Donald Trump takes office with a new cost-cutting agenda.

The outgoing leader unveiled the money for the International Development Association as he attends the G20 summit underway in Rio de Janeiro, his last time at the gathering of world leaders.

"The president announced today that the United States intends to pledge $4 billion over three years... which is really exciting," a senior US administration official told reporters on condition of anonymity.

The official said the pledge would not be binding on Trump’s incoming administration but said previous Republican governments had also backed top-ups for the fund.

US Deputy National Security Adviser Jon Finer earlier called the pledge "historic" and said Biden would "rally other leaders to step up their contributions."

The International Development Association is the concessional lending arm of the World Bank and is used for some of the poorest countries in the globe, including for projects focused on climate.

During a six-day tour of South America, Biden has been trying to shore up his international legacy ahead of President-elect Trump’s return to the White House on January 20.

On Sunday he visited the Amazon rainforest in Brazil to promote his record on climate change, saying that the United States had hit its target of increasing bilateral climate financing to $11 billion a year.

Billionaire Trump has pledged to take a wrecking ball to many of Biden’s policies and has appointed tech tycoon Elon Musk as head of a commission to target what he calls federal government waste.