Aid workers and U.N. peacekeepers are trading food for sex with young girls in Liberian camps housing those left homeless by years of war, an aid group said Monday.

Save the Children, which surveyed nearly 160 children and about 170 adults who were either living in camps or had recently returned home, said they were repeatedly told of girls having sex with older men in exchange for money, food and other goods.

The accused included peacekeeping troops, aid workers and other powerful men in the community. The report did not give the nationality of the aid workers or peacekeepers involved. About 17,000 U.N. peacekeepers are based in Liberia.

Despite some initiatives to reduce sexual exploitation and abuse, the report said there had been "little change" in the lives of vulnerable children since 2002.

CountryWatch: Liberia

Liberia is just starting to recover from years of civil war and many of its citizens still live in camps set up after they were forced out of their villages.

The U.N. humanitarian coordinator in Liberia, Jordan Ryan, said the survey was outdated because it was conducted nine months ago and much has improved since then. The camps that are the primary subject of the report are now closed, he said.

"There are good things that are now happening in Liberia," he said. U.N. staff who engage in such "unacceptable behaviors" are fired, Ryan added.

President Ellen Johnson-Sirleaf took office in January, promising reconstruction and peace.

"With the coming in of a new government, mechanisms are being put in place to limit these kinds of things," said Mohammed Sheriff, Liberia's deputy health minister.

But Sheriff cautioned that preventing sex transactions is a difficult task for a poor country still recovering from years of violence.

"We have parents that have so many children — eight to 10 — that are not able to cope with the meager amount of money they have," he said. "People live below 25 cents (per day); so you can look at reasons why these thing may happen."