Pressure on Ivory Coast's incumbent leader Laurent Gbagbo to cede power to his electoral rival mounted Tuesday from the west African nation's neighbours, United Nations and the United States, which appealed for a "peaceful transition".

The Economic Community of West African States (ECOWAS), a regional bloc, suspended Ivory Coast over the crisis and called on Gbagbo to yield power as it recognised opposition leader Alassane Ouattara as the new president.

"For now, we have suspended Cote d'Ivoire from all our activities," Nigerian President Goodluck Jonathan said following an emergency ECOWAS summit in Abuja.

"We believe that the result declared by the electoral commission ... is the authentic one, and that Ouattara is the person who we support as the president of Cote d'Ivoire."

The United States also piled pressure on Gbagbo with US State Department spokesman Philip Crowley saying "it is time for President Gbagbo to recognise the will of the people of Cote d'Ivoire and embark on a peaceful transition." Otherwise, he warned, the country faces "isolation from the global community."

But Gbagbo raised the stakes in the crisis, with his allies announcing a new government to rival the one declared by Ouattara.

International mediators are trying to break the deadlock amid warnings that the country could erupt into violent unrest. However non-essential staff for the UN mission "have begun leaving the country," a UN official in Abidjan told AFP, without giving details. The United Nations in New York put at 460 the number of staff it planned to relocate from Ivory Coast.

UN special envoy to Ivory Coast, Choi Young-jin, reaffirmed to the Security Council on Tuesday that he considered Ouattara to be the winner of the landmark election by "a clear margin".

But Russia held up a council statement on the issue saying the UN had exceeded its mandate by naming Ouattara the winner, a position that US ambassador Susan Rice called "quibbling", saying it would acknowledge the results declared by the Ivorian electoral commission.

Gbagbo and Ouattara have both sworn themselves in as president and each has named its own government, leaving Ivorians anxious about how the standoff will be resolved.

The streets of Ivory Coast's main city Abidjan filled with traffic and pedestrians after several days of tense quiet, but residents remained concerned on Tuesday.

Meanwhile Guillaume Soro, who has been reappointed prime minister by Ouattara, said that measures were being taken "to ensure that control of the finances is given to my government... We are convinced that by the end of this week we will see these measures having a real effect."

He reiterated his side's allegations that Gbagbo was attempting a "coup d'etat". "We are not yet at the stage of using force," he added in Tuesday's statement.

In Abuja, Jonathan said ECOWAS was not interested in a negotiated unity government in Ivory Coast because such previous arrangements in other nations have stumbled.

"From the experience we have had so far in Kenya and in Zimbabwe, it has never really worked and that's why we don't want to contemplate that," he said.

Ivory Coast's election was supposed to ensure peace but instead has been marred by deadly violence. Human rights group Amnesty International said at least 20 people have been shot dead since the vote on 28 November.
Gbagbo has extended a nightly curfew to curb disturbances.