The UN has faced a string of abuse allegations against peacekeepers

The UN said a unit of its contingent in Bouake, a northern rebel stronghold, had been confined to base.

It has confirmed that some Moroccan troops are under investigation.

Claims of sexual abuse have been made against UN troops on various missions, prompting ex-UN chief Kofi Annan to declare a "zero tolerance" policy.

'Utterly immoral'

"There have been crimes such as rape, paedophilia and human trafficking," he said in December 2006, shortly before leaving office.

He said sexual exploitation and abuse were "utterly immoral" and at odds with the UN mission, and would be punished.

Sexual abuse and exploitation by peacekeeping personnel hit the headlines in 2004 after a UN report detailed widespread abuse in the DR Congo involving UN troops.

More than 300 members of UN peacekeeping missions around the world have been investigated for sexual exploitation and abuse since 2004, including some stationed in Congo, Cambodia and Haiti.

A UN statement said the latest allegations had been uncovered by an internal inquiry, and a full investigation was now under way.

"But due to the serious nature of the allegations, the United Nations has taken the decision to suspend all activities of the contingent and has cantoned the unit within its base," it said.

UN SEXUAL ABUSE SCANDALS 2003 - Nepalese troops accused of sexual abuse while serving in DR Congo. Six are later jailed 2004 - Two UN peacekeepers repatriated after being accused of abuse in Burundi 2005 - UN troops accused of rape and sexual abuse in Sudan 2006 - UN personnel accused of rape and exploitation on missions is Haiti and Liberia 2007 - UN launches probe into sexual abuse claims in Ivory Coast

The exact nature of the alleged offences has not been officially disclosed, but they are believed to involve sex with underage girls.

About 9,000 troops serve under the UN in Ivory Coast, which has been split between areas controlled by government and rebel forces.

The UN Security Council this week voted to extend the mission until January, in the hope that it can help create the conditions for elections, that have repeatedly been delayed.

According to the UN website, troops in Bouake come from Morocco, Pakistan, Bangladesh and Ghana.

The UN has confined its entire force in the town to barracks.

It is a sign of how seriously the UN is taking these latest accusations, says the BBC's Peter Miles.