African leaders returned to Ivory Coast on Monday, their second visit in a week to pressure the renegade president to cede power more than a month after he was voted out of office.

Laurent Gbagbo has defied calls to step down — and threats of a military ouster — even though results tallied by the country's electoral commission and certified by the United Nations showed he lost the election to longtime opposition leader Alassane Ouattara.

Gbagbo has clung to power with the backing of the army, and human rights groups accuse his security forces of abducting and killing hundreds of political opponents. The UN says it also has been barred entry from two suspected mass graves.

Gbagbo has dismissed the international condemnation as "a foreign plot" led by France, the country's former colonizer.

The three presidents who were coming to Abidjan on Monday represent the Economic Community of West African States, or ECOWAS. The 15-member regional bloc is threatening military action if Gbagbo does not agree to step aside.

In a break with the past, the African leaders are uniting to take a stand against one of their own.

A delegation of West African leaders is renewing efforts to get incumbent Ivory Coast leader Laurent Gbagbo to step down. (Thierry Gouegnon/Reuters)

The presidents of Benin, Sierra Leone and Cape Verde are also being joined by Kenyan Prime Minister Raila Odinga, who is representing the African Union.

An official from Odinga's office said the renegade leader would be guaranteed safety if he agrees to hand over power and chooses to stay in Ivory Coast or go elsewhere.

The official, who spoke on condition of anonymity because he did not have permission to speak with the press, did not have further details on the amnesty, but said the deal offered by the African leaders was non-negotiable.

Col. Mohammed Yerima, director of defence information for the Nigerian military, said defence chiefs from ECOWAS met Friday to discuss what sort of assault they would use if talks fail.

He said any initial invasion force would rely on the West African coalition's standby force, as well as equipment and material that has already been stockpiled.

Gbagbo, who came to power in 2000 and ruled during a brief civil war, overstayed his mandate when it expired in 2005, claiming the country was too unstable to organize a poll. After many delays and postponements, an election was held in November.

For several days after the vote, Gbagbo loyalists tried to prevent the election commission from releasing the results. When the results finally were released, the constitutional council led by a Gbagbo adviser immediately overturned them by cancelling half a million ballots from opposition strongholds.

Gbagbo's government then imposed a media blackout, yanking foreign channels off the air. He called on the UN peacekeeping mission to leave the country, accusing it of backing his opponent. Ouattara is holed up in a luxury hotel in Abidjan, the commercial capital.

The election was intended to help reunify Ivory Coast, which was divided by the 2002-2003 war into a rebel-controlled north and a loyalist south. Instead, the election has renewed divisions that threaten to plunge the country back into civil war.