By Paul Welsh BBC correspondent in Ivory Coast

Human rights investigators sent to Ivory Coast by the United Nations secretary general say they have no doubt that atrocities have been committed.

The investigators were asked to study allegations of abuses by both sides in the conflict.

It's absolutely important to accelerate the peace process Betrand Ramcharan UN rights team

They have now left to prepare their report and their recommendations for the UN head.

The team of UN officials and forensic experts was sent to Ivory Coast because claims of human rights abuses in the country are mounting and mass graves have been found.

They met President Laurent Gbagbo and the rebels, human rights groups and other organisations - they heard reports of systematic abuse in government-held areas and summary executions by the rebels.

They were taken to the site of a mass grave in the rebel stronghold, Bouake, and said they hoped to return to the sites of graves in the future to investigate properly.

The mission was led by the UN Deputy High Commissioner for Human Rights, Betrand Ramcharan.

He says he has no doubt that there have been violations of human rights here and that much needs to be done to stop more taking place.

Elusive peace

"I think that we've heard enough to say that there have been violations of human rights on different sides of the conflict," Mr Ramcharan said.

"It's absolutely important to accelerate the peace process because if we don't do this I think that there are great dangers here for human rights."

Mr Ramcharan said there is need for more humanitarian help in the areas worst affected by the fighting of the last four months and that the two sides of the conflict have to be persuaded to work for peace.

But peace is proving elusive.

France brought in more reinforcements on Saturday to prevent the shaky ceasefire between the government and the original rebel movement from breaking down, and to stop the new rebel movement in the west moving deeper into government-held areas.