By Evelyn Leopold UNITED NATIONS, July 21 (Reuters) - Moroccan U.N. peacekeepers in Ivory Coast are alleged to have sexually abused girls as young as 13 over a three-year period as units rotated through the West African country, U.N. officials said. The United Nations said on Saturday it had suspended the Moroccan contingent from its peacekeeping mission in Ivory Coast during an investigation. The entire battalion of 734 soldiers had already been confined to barracks. Two U.N. officials identified the peacekeepers as Moroccans and one said entire contingents had been involved with the young girls passed from unit after unit, resulting in the birth of illegitimate children. The officials spoke on condition of anonymity because they were not authorized to speak publicly. Over the last few years as peacekeeping has expanded, reports of abuse have mounted in various African nations, especially in the Democratic Republic of the Congo, prompting the world body to declare a "zero-tolerance" policy. The United Nations can investigate but is powerless to punish perpetrators, who can be sent home for prosecution. Moroccan troops were involved in sexual abuse in eastern Congo and two years ago the Rabat government arrested six soldiers. The Ivory Coast mission numbers just over 9,000 uniformed personnel from more than 40 countries. Moroccans make up the bulk of the force in Bouake, a rebel stronghold in the north, with some Bangladeshi police, Pakistani engineers and Ghanaian medical personnel. The Moroccan U.N. mission had no immediate response to the allegations. A U.N. statement on Friday had said a full investigation was underway into "serious allegations of widespread sexual exploitation and abuse by a U.N. military contingent serving in Bouake." "It means they don't participate in our operations," Hamadoun Toure, spokesman for the U.N. mission in Ivory Coast, said on Saturday. "Those who are found guilty will be sent back home." The U.N. Security Council voted this week to extend the mandate of peacekeeping forces in Ivory Coast until January to help create peaceful conditions for elections that have been repeatedly delayed. The peacekeepers, backed by troops from former colonial power France, are in Ivory Coast to support a peace process that was revived in March by an agreement between President Laurent Gbagbo and rebel leader Guillaume Soro. A 2005 U.N. report said peacekeeping soldiers should be punished for any sexual abuse, their pay docked and a fund set up to assist any women and girls they impregnated. But many member nations have not agreed. (Additional reporting by Claudia Parsons)