(CNN) -- Child witchcraft allegations are increasing in parts of Africa, as thousands of children have been attacked, beaten or killed, according to a new report.

The accused children are mostly boys, ages 8 to 14 -- with orphans, street children, albinos, and disabled as the most at risk, said the United Nations Children's Fund in its report.

The accused children often suffer from extreme physical or psychological violence as a result of being branded a "child witch," the report said.

Exorcisms that include pouring petrol into children's eyes or ears, and forcing them to swallow various substances have been reported by researchers as ways to "cleanse" the accused.

The agency cites urbanization, poverty, conflict and the growing economic burden of raising children as some of the factors that contribute to the recent increase in accusations against already vulnerable children.

Countries with the highest prevalence of child witchcraft accusations are: Angola, Benin, Cameroon, Central African Republic (CAR), Democratic Republic of Congo (DRC) and Nigeria, the report said.

The issue of child witches is a relatively recent phenomenon that dates back 10 to 20 years. Researchers say before this, women and the elderly were the ones most often accused.