West African leaders said they would use "legitimate force" to remove Laurent Gbagbo from power in Ivory Coast if he does not agree to step down peacefully, a call that comes amid rising fears of violence.
At least 173 deaths have been confirmed in violence over the presidential vote, and the UN is warning the number could be greater since it has been unable to investigate all the allegations.
Masked gunmen with rocket launchers have blocked access to what officials believe may be a mass grave site in Ivory Coast, the United Nations said.
The UN reported that heavily armed forces allied with Gbagbo and joined by masked men, were preventing people from getting to the village of N'Dotre, where the global body said "allegations point to the existence of a mass grave."
The UN did not elaborate on the possible victims, though it has expressed concerns about hundreds of arrests, and dozens of cases of torture and disappearance during the political turmoil since the presidential runoff vote was held nearly a month ago.
Alain Toussaint, an adviser for Gbagbo, has said that he didn't believe soldiers or people close to Gbagbo would carry out the acts of violence that have been reported.
Gbagbo has refused to step down from the presidency despite international calls for his ouster from the UN, US, former colonizer France, the European Union and the African Union. The international community recognizes Alassane Ouattara as the winner, though Gbagbo maintains control of the national military.
James Gbeho, president of the regional bloc ECOWAS — the Economic Community of West African States — said the group of West African leaders was making an "ultimate gesture" to Gbagbo to urge him to make a peaceful exit.
The 15-nation regional bloc of West African states made the decision following a six-hour emergency summit in Abuja, Nigeria, on Ivory Coast as worries mounted that the country that suffered a 2002-2003 civil war could return to conflict.
Gbeho said the bloc would send in a high-level delegation to meet with Gbagbo, and tell him to step down.
Gbagbo claimed victory in the presidential election only after his allies threw out half a million ballots from Ouattara strongholds in the north, a move that infuriated residents there who have long felt that they are treated as foreigners in their own country by southerners.
"In the event that Mr. Gbagbo fails to heed this immutable demand of ECOWAS, the Community would be left with no alternative but to take other measures, including the use of legitimate force, to achieve the goals of the Ivorian people," a statement from ECOWAS said.
Gbeho said chief of defense staffs should meet "to plan future actions, including provision of security along the Ivory Coast-Liberia border, in the event that their message is not heeded."
Ivory Coast was once an economic hub because of its role as the world's top cocoa producer. The 2002-2003 civil war split the country into a rebel-controlled north and a loyalist south. While the country officially reunited in a 2007 peace deal, Ouattara draws his support from the northern half of the country, where he was born, while Gbagbo's power base is in the south.Reuse content