In its first intervention since the conflict began three months ago, the Council said it was gravely concerned about the consequences of the fighting for the country and the region.

The Council firmly condemns attempts to use force to influence the political situation in C�te d'Ivoire and to overthrow the elected government UN Security Council

In a separate move, UN Human Rights Commissioner Sergio Vieira de Mello has announced he is sending an envoy to Ivory Coast to report on alleged abuses of civilians.

Ivory Coast rebels began their uprising in September and hold about half of the country - the world's largest cocoa producer.

They have reportedly seized the town of Bangolo, about 40 kilometres (25 miles) from the city of Man, which rebels recaptured on Thursday.

And for the first time, Ivory Coast's top opposition leader, Alassane Ouattara, has urged President Laurent Gbagbo to resign and call fresh elections.

Ivory Coast, previously seen as a beacon of peace and prosperity in a strife-torn region, has been divided in two, with rebels controlling the largely Muslim north.

Truce search

The 15-member Council adopted a statement on Ivory Coast on Friday.

It condemned "attempts to use force to influence the political situation and overthrow the elected government".

"In particular the Security Council welcomes the commitment by the President of C�te d'Ivoire [Ivory Coast's French name] to submit in the coming days a comprehensive plan to end the crisis."

It praised the contribution of France - Ivory Coast's former colonial power - which has sent troops to the country.

Members expressed "deepest concerns at reports of mass killings and serious violations of human rights" and welcomed the dispatch of a mission to gather precise information regarding violations of human rights and of international humanitarian law.

Rebel advance

An unidentified military source quoted by the French news agency, AFP, said that rebels have taken the town of Bangolo.

According to local people, government troops in the city did not put up any resistance.

"The rebels entered the town virtually without a fight," a resident told AFP.

Ouattara has fled to Gabon

The neighbouring town of Man was recaptured on Thursday by two rebel groups, the Patriotic Movement for the Great West and the Movement for Justice and Peace, which say they have merged into a single grouping, the MJP.

Alassane Ouattara, who has been in exile in Gabon for the last few weeks, has said he will urge the rebels to take part in peace talks.

"I have not had any contact with them, but now I am going to contact all the rebel groups and tell them they should accept to get into the process of discussion and negotiations," he told the BBC's Focus on Africa programme.

Mr Ouattara, who was speaking in the Senegalese capital Dakar, where he has met President Abdoulaye Wade, said that he would tell Mr Gbagbo to stand down and call early elections if he met him face to face.

"Ivory Coast is in a terrible mess. The only way to get out of this crisis is to have early elections," he said.