Children have been subjected to rape and prostitution by United Nations peacekeepers in Haiti and Liberia, a BBC investigation has found.
Girls have told of regular encounters with soldiers where sex is demanded in return for food or money.
A senior official with the organisation has accepted the claims are credible.
The UN has faced several scandals involving its troops in recent years, including a DR Congo paedophile ring and prostitute trafficking in Kosovo.
Under UN regulations, military personnel cannot be prosecuted in the country where they are serving, and it is up to the courts in their home countries to prosecute crimes committed.
The UN said it had firm knowledge of only two concrete examples of sex offenders being sent to jail, although it believed there could be others it did not know about.