Candidates to be the next president of the World Bank are being announced as the deadline for nominees approaches.
Three African countries have endorsed the nomination of Nigerian Finance Minister Ngozi Okonjo-Iweala.
The US is yet to name its candidate, but former White House adviser Larry Summers has been mentioned.
The US has always held the position since the World Bank was founded in 1944 but there is pressure for the next head to be from a developing nation.
The deadline for nominations to replace Robert Zoellick is 18:00 Washington time (22:00 GMT) on Friday.
US development economist Jeffrey Sachs has been nominated by smaller developing countries, such as Bhutan, East Timor, Haiti, Kenya, Guatemala and Chile, but he acknowledges that he does not have President Obama's support.
Prof Sachs argues that the World Bank should be led by a development expert.
Former Colombian finance minister, Jose Antonio Ocampo, now looks unlikely to be nominated after Colombia's current finance minister, Juan Carlos Echeverry, said on Thursday that the country was instead focusing on a bid for the presidency of the International Labour Organization.
Mr Ocampo had agreed to stand and had the backing of Brazil, but also needed Colombia's support.
In a joint statement, Angola, Nigeria and South Africa pledged their support to Ms Okonjo-Iweala.
"The endorsement is in line with the belief that the appointment of the leadership of the World Bank and its sister institution, the International Monetary Fund, should be merit-based, open and transparent," the statement said.
Speaking at a news conference, Mrs Okonjo-Iweala said: "I consider the World Bank a very important institution for the world, and particularly for developing countries deserving of the best leadership, so I look forward to a contest of very strong candidates.
"And am I confident? Absolutely."
Other names in the running to be the official US candidate include Indra Nooyi, the Indian-born head of Pepsi, and Susan Rice, the US ambassador to the United Nations.
With the US holding the most votes at the World Bank, which has 187 members, the vote on the next president should be a formality.
Calls to end 'monopoly'
The World Bank and the International Monetary Fund were created at the conference at Bretton Woods in 1944 as a means to regulate trade between nations in the aftermath of the Great Depression and World War II.
A US national traditionally heads the World Bank while a European runs the IMF - currently France's Christine Lagarde.
But emerging economies have become increasingly unhappy with this arrangement and are pushing for change.
In a recent edictorial, three former chief economists of the World Bank - Francois Bourguignon, Nicholas Stern and Joseph Stiglitz - argued for an end to the US "monopoly" on running the institution.
"To say it is merit-based, and to choose an American repeatedly, shows scant respect to the citizens of other countries," they wrote.
Fredrik Erixon, a former World Bank economist, told the BBC that the selection process was "anachronistic" but he still expected the White House nominee to be the successful candidate.
The current president, Robert Zoellick, is to step down from his role at the institution when his five-year term comes to an end on 30 June.
Mr Zoellick, 58, was nominated for the role in 2007 by George W Bush.