U.N. chief Ban Ki-moon moved Wednesday to set up an independent external review of how the United Nations handled allegations of sexual abuse of children by French and African troops in the Central African Republic.

The United Nations has been badly shaken by accusations that it failed to act quickly to respond to the serious allegations of child sexual abuse at a camp for displaced civilians from December 2013 to June 2014.

The U.N. human rights chief said Saturday he had asked several countries to probe allegations of rape and killings by their troops in the Central African Republic following reports of child abuse by French peacekeepers.

A statement said the allegations concerning soldiers from other countries were "very serious" and ranged from executions, abductions to rape.

The interim president of the Central African Republic, Catherine Samba Panza, urged rich donor countries Tuesday to deliver on aid promised to her war ravaged nation, including funds to pay for elections later this year.

"I reaffirm my determination to organize democratic and credible elections... which will whatever the case take place before the end of 2015," Samba Panza told reporters after a donor's conference at EU headquarters in Brussels.

Armed groups in strife-torn Central African Republic released 350 child soldiers Thursday, honoring a deal signed with UNICEF, the United Nations children's agency said.

"After two years of heavy fighting, the release of children by these groups ... is a real step towards peace," said UNICEF's representative in Bangui, Mohamed Malick Fall. 

Nelson Mandela's widow, Graca Machel, joined prominent activists on Wednesday to call for a full inquiry on sexual abuse by U.N. peacekeepers and personnel following the furor over alleged child sexual assault by French troops in the Central African Republic.

The campaign dubbed "Code Blue" is to demand change in the United Nations' handling of sexual abuse allegations and hopes to enlist countries in a push for action.

Several hundred people, some in military uniforms, demonstrated Tuesday in the capital of the restive Central African Republic over a peace forum's recommendation that upcoming general and presidential elections be delayed.

The protesters, who erected barricades and burnt tires on major roads, including the road linking Bangui to the airport, also demanded that the country's interim President Catherine Samba-Panza step aside.

U.N. rights chief Zeid Ra'ad Al Hussein on Friday said France should have probed much earlier claims that its soldiers raped children in the Central African Republic between December 2013 and June 2014.

Zeid said the delayed response was all the more difficult to comprehend since people other than the accused must have known of the abuse but not passed the information up the military hierarchy.

The Central African Republic will take legal action against the French soldiers accused of raping children in exchange for food at a refugee camp, the country's justice minister said Wednesday.

"Legal action will be pursued... These are still very serious acts," said Justice Minister Aristide Sokambi, insisting his nation was not targeting France but individual soldiers. 

A U.N. tribunal has ordered the reinstatement of Swedish official Anders Kompass who was suspended for leaking a report to France about child abuse by French soldiers sent to the Central African Republic in 2014.

The ruling of the internal tribunal was delivered on Tuesday and Kompass "has thus resumed his service," a spokesman for the U.N. human rights office told AFP.

Flimsy tents and filthy corrugated iron huts dot the landscape at M'Poko, the refugee camp at Bangui airport where French troops allegedly raped hungry children in exchange for food.

Many children in the desolate camp -- home to more than 100,000 during the bloodiest days of the crisis in the the Central African Republic last year -- were orphans, forced to fend for themselves for food and water.