Heavy gunfire and explosions have gripped Ivory Coast's main city, Abidjan, as a battle for control of the country raged outside the presidential palace and the home of incumbent president Laurent Gbagbo.
Residents hid in their homes as fighters for internationally-recognized president Alassane Ouattara battled forces still loyal to Mr. Gbagbo.
It was not clear if Mr. Gbagbo was inside his home, in the presidential palace or elsewhere. A Paris-based advisor, Alain Toussaint, said Friday that Mr. Gbagbo has no intention of ceding power.
A spokesperson for the U.N. mission in Ivory Coast, Hamadoune Toure said that the mission offered to transport Mr. Gbagbo out of the country to help resolve the crisis.
Mr. Ouattara has been declared the winner of a November presidential election, but Mr. Gbagbo has refused to step down and has been able to stay in control largely with the military's help.
However, fighters loyal to Mr. Ouattara met little resistance from pro-Gbagbo troops when they swept into Abidjan Thursday, after a fast-moving offensive through the country in which they captured town after town.
On Friday, U.N. Secretary-General Ban Ki-moon urged Mr. Gbagbo to hand over power and warned both sides that anyone who commits human rights violations will be held accountable. Both Gbagbo and Ouattara supporters have been accused of abuses.
The U.N. High Commissioner for Refugees (UNHCR) said there are reports of extrajudicial killings, the killing and maiming of children and sexual violence.
Special Rapporteur Chistof Heyns cited reports that civilians are being killed for expressing their political affiliation.
The United Nations says more than 490 people have been killed since the political crisis began in early December. It says up to one million have fled, including thousands who have crossed into neighboring Liberia and Ghana.
The African Union, United Nations, the West African bloc ECOWAS, France and the United States have called on Mr. Gbagbo to give up.
Some information for this report provided by AP, AFP and Reuters.