UN peacekeepers in Ivory Coast are doing everything possible to gain access to those areas where human rights abuses are alleged to have occurred, the United Nations said.

The world's top cocoa producer was plunged into crisis after Laurent Gbagbo refused to step down as president after a disputed election in November, triggering violence in a nation still divided after a 2002-03 civil war.

Ivory Coast's electoral commission, world leaders and the 192-nation UN General Assembly have recognized challenger Alassane Ouattara as the winner.

"The Secretary-General (Ban Ki-moon) told President Ouattara that he was alarmed by the reports of egregious human rights violations," U.N. spokesman Martin Nesirky said in a statement, referring to a telephone conversation between Ban and Ouattara on Saturday.

"He (Ban) said UNOCI had been instructed to do everything possible to gain access to the affected areas both for prevention and to investigate and record the violations so that those responsible will be held accountable," Nesirky said.

The U.N. peacekeeping mission in Ivory Coast, known as UNOCI, said last month that pro-Gbagbo forces were blocking access to what could be a mass grave near Abidjan. U.N. diplomats told Reuters UNOCI was still barred from the site.

Ouattara reiterated in his call with Ban that he wanted "an early International Criminal Court investigation as a credible signal for accountability."

Last week Ouattara asked The Hague-based court to send a mission to the West African nation to investigate reports of post-election violence committed by pro-Gbagbo forces.