Rights chief Zeid Raad al-Hussein urged the countries to investigate whether troops they later assigned to UN missions sexually abused children. A six-page UN report details the alleged abuse by troops from France, Chad and Equatorial Guinea between December 2013 and June 2014 at a center for displaced people at M'Poko airport in the Central African Republic (CAR) capital, Bangui.

"In the wake of the revelations of alleged serious sexual abuse of children, currently under investigation by the French authorities, my office has taken a deeper look into these issues and the extent of the follow-up into alleged serious violations," Hussein said in a statement.

"Some of these incidents have been at least partly investigated, and some states have apparently sanctioned some of the soldiers involved." He added: "It is important to do a thorough review of what happened in the past, but also to drive home the message that there must be no repetition of these dreadful acts now or in the future."

The United Nations has also launched an internal investigation into its handling of the allegations. The UN apparently has no specific guidelines on how to handle accusations of child sexual abuse and no requirement for immediate, mandatory reporting.

France intervened in former colony CAR 19 months ago amid fighting between Christian and Muslim militias and started withdrawing its 2,000 troops this year, handing over to UN peacekeepers.

'Serious crimes'

The United Nations has come under fire for its slow response after preparing its initial 2014 report on the allegations. UN officials only began talking openly about the issue a month ago, after an article on the allegations appeared in Britain's Guardian newspaper. However, UN investigators had heard the stories of sexual abuse from several boys back in May and June 2014.

"There must be accountability for serious crimes, no matter who commits them," Hussein said Saturday.

On Friday, the non-governmental organization AIDS-Free World released new documents that bolstered the case for an independent investigation. The new evidence seems to show that UN officials did not move quickly to support France's inquiry into the allegations and had instead devoted resources to vetting the human rights staffer who blew the whistle.

Stephane Dujarric, the spokesman for UN Secretary-General Ban Ki-moon, told reporters that the documents "may or may not be authentic," adding that Ban had only recently heard the allegations himself.

Children have also been forced to fight in CAR.

mkg/jr (Reuters, AP)