As the world body seeks to crack down on the abuse, it could bar countries from participating in missions if they fail to prosecute offenders, even though the UN is hard pressed to find contributing nations, the officials said on Friday.
Rocked by widespread abuse of women and girls, including gang rape, in the Democratic Republic of the Congo, the United Nations also has found sexual exploitation cases in at least four other missions - in Burundi, Liberia, Ivory Coast - as well as more recently in Haiti, they added.
"We think this will look worse before it begins to look better," Jane Holl Lute, assistant secretary-general for peacekeeping operations, said. "We expect that more information will come from every mission on allegations. We are prepared for that."
The undersecretary-general for peacekeeping, Jean-Marie Guehenno, said that up until now the UN had avoided identifying countries that were slow to court-martial their troops, but that he had demanded action within weeks in some cases.
"They are aware of a very direct threat which is that if they don't get their act together, we are going to tell them to get out of their mission," Guehenno said, referring to all of the peacekeeping missions and not just the Congo.
"We do share concerns that sexual abuse could be widespread, could exist in other places"
US State Department spokesman
There are nearly 11,000 military personnel in the Congo to help keep the peace after a civil war. The force is the largest among the more than 60,000 soldiers in UN peacekeeping operations around the world.
The United States, whose support is essential for peacekeeping missions, said it shared the UN's fears and wanted the world body to make preventing further abuses a priority.
"We do share concerns that sexual abuse could be widespread, could exist in other places," State Department spokesman Richard Boucher told reporters, noting Washington believed the idea of naming countries that fail to act against offenders was worth considering.
"We have worked very carefully with the UN to try to get them to ... make sure that in fact prevention becomes a top priority for UN peacekeeping operations and troop contributors."