U.S. President Barack Obama faces a Friday deadline to nominate a convincing candidate for the World Bank presidency amid signs emerging-market member countries are set to push for a candidate of their own.

The Obama administration could have started the campaign to win global approval for its nominee, but didn't. Now it faces the challenge of coming up with someone prominent enough to blunt the diplomatic drive by the emerging markets' loosely organized but increasingly vociferous group.

That vaguely defined constituency includes nearly all of Latin America, Africa and Asia.

If the U.S. position is less than certain, the emerging markets' strategy is even less so. Till late Thursday there was little indication of a consensus, with two -- a Latin American and a Nigerian -- and not one candidate from the developing world still tipped to compete for the top post.

Nigerian Finance Minister Ngozi Okonjo-Iweala -- a woman of widely recognized credentials -- and Colombia's former Finance Minister Jose Antonio Ocampo were due to be nominated as candidates for the presidency. There was no indication of a last-minute agreement for either of the two candidates to endorse the other and withdraw from the contest.

The World Bank's presidency traditionally has gone to an American, but challenges to that convention have become more pronounced in recent months, especially after Frenchwoman Christine Lagarde successfully disarmed opposition to her leadership of the International Monetary Fund.

Lagarde campaigned vigorously to win international support, and her gender played a key part in the approvals she won worldwide.

Judging by that example, the Obama administration is weighing the strategy of putting forward an eminent woman candidate to blunt some of the opposition being directed at a potential U.S. nominee.

The U.S. ambassador to the United Nations, Susan Rice, is seen as a prime candidate, but there is no indication she wants the job. Other U.S. candidates tagged on the diplomatic grapevine include Lawrence Summers, a former treasury secretary, and Jeffrey Sachs, director of the Earth Institute at Columbia University. Sachs has support from some but not all of the developing countries.

Opposition to the U.S. leadership of the World Bank combines different political hues -- from populist, explicit critics of the United States to U.S. friends in the emerging markets who insist it's their turn to lead the bank.

Ocampo told the Financial Times support for his candidacy and that of Okonjo-Iweala showed the developing countries "can put good and credible candidates -- perhaps as good as or better than the U.S. candidates." The Nigerian also served previously as a World Bank managing director.

Ocampo said merit rather than nationality should rule the choice of leadership at the World Bank. He said the bank's practice of having a U.S. chief since formation in 1944 was "anomalous" when compared with the "open" contest for the top jobs at the United Nations, the World Trade Organization and the Organization of Economic Cooperation and Development.

"We have joined this race in the expectation that this time it would be different," Ocampo told the Financial Times.