GENEVA (AFP) - Key WTO ambassadors tapped Nigeria's Ngozi Okonjo-Iweala Wednesday as the best pick to lead the organization, but she was opposed by Washington, who said it supported South Korean Trade Minister Yoo Myung-hee instead.

The so-called troika of ambassadors heading the World Trade Organization's three main branches determined after four months of consultations with member states that Okonjo-Iweala was the most likely to obtain the consensus needed to take the top job, WTO spokesman Keith Rockwell told reporters.

The initial pool of eight candidates for the WTO's top post had been whittled down to just two over two previous rounds of consultations, with only Okonjo-Iweala and South Korean Trade Minister Yoo Myung-hee left in the race.

The global trade body is thus set to be led by a woman for the first time whichever of the two final candidates succeeds in their bid to follow Roberto Azevedo, who stepped down as WTO director-general in August a year ahead of schedule.

The troika, led by New Zealand's Ambassador David Walker, concluded a third round of consultations on Tuesday.

Its decision marks an important step paving the way for Okonjo-Iweala to become the first woman and the first African to head the organization.

But the WTO's 164 member states still need to determine whether they will support her before their next General Council meeting on November 9.

And on Wednesday, Washington already said it was opposed to her taking the helm,

casting doubt on whether she can obtain the necessary full backing from member states.

Rockwell said that 27 delegations had taken the floor during Wednesday's meeting.

''One delegation could not support the candidacy of Dr. Nogzi and said they would continue (supporting) South Korean minister Yoo,'' he said.

''That delegation was United States of America.''

Rockwell meanwhile stressed that Wednesday's meeting ''was never intended to make a final decision on our next DG (director general).''

''That decision can only be taken by the General Council,'' he said.

Okonjo-Iweala, 66, who served as her country's first female finance and foreign minister and has a 25-year career behind her as a development economist at the World Bank, welcomed the troika's support.

''Dr. Ngozi is immensely humbled to receive the backing of the WTO's selection committee today,'' a spokesperson told AFP in an email.

''She is honored by the faith members have placed in her.''

Okonjo-Iweala voiced confidence earlier this month that she would be the successful candidate.

''I feel the wind behind my back,'' she told a virtual press briefing after the 55-member African Union officially supported her.

Okonjo-Iweala, who also serves on Twitter's board of directors, as chair of the GAVI vaccine alliance and as a special envoy for the World Health Organization's Covid-19 fight, saw her candidacy get another boost this week when the EU threw its weight behind her.

If she does obtain consensus backing, she would be the first woman and the first African to lead the global trade body in its 25-year history.

And she would certainly have her hands full in the new position.

Even before the Covid-19 crisis hit, the WTO was already grappling with stalled trade talks and struggling to curb tensions between the United States and China.

The global trade body has also faced relentless attacks from Washington, which has crippled the WTO dispute settlement appeal system and threatened to leave the organization altogether.

Okonjo-Iweala said earlier this month that she had broad experience in championing reform and was the right person to help put the WTO back on track.

''I am a reform candidate and I think the WTO needs the reform credentials and skills now.''