Socially accepted practices are being used to hide the sexual abuse of children in various parts of the world, according to a new report from an international advocacy group.

Girls are bought, through payment of a dowry, to provide sexual pleasure... and are then abandoned Carmen Madrinan, ECPAT executive director

The Bangkok-based international child protection campaign group, ECPAT (End Child Prostitution, Child Pornography and Trafficking of Children for Sexual Purposes) reserves its harshest criticism for forced marriages of adolescents and children.

It says such marriage contracts can be found all over the Middle East and South Asia and are a cloak for child abuse.

BBC correspondent Stephen Cviic says international non-governmental organisations often tread a fine line in promoting a progressive view, and the strong criticism in this report may well be unpalatable to people in developing countries.

The ECPAT notes that in Iran the legal age for marriage is 13, which means that older men can have sex with young girls.

The girls are essentially "bought, through payment of a dowry, to provide sexual pleasure... and are then abandoned," says Carmen Madrinan, the executive director of ECPAT International.

And Egyptian children are often given to wealthy older men for a few weeks or months under legal short-term marriage contracts, it says.

Boy prostitution

The report also describes the problem of prostitution among underage boys in South Asia, which is never discussed openly because of religious and sexual taboos.

In Pakistan, it says, the use of boys as homosexual prostitutes for older men is virtually tolerated, but the boys themselves are unable to seek help from the police because they are seen as outcasts.

"It's a phenomenon that was hidden for a long time, and then we found that it's everywhere, but nobody really mentioned it," said Chitraporn Vanasapongse, who wrote the report.

The report describes other traditional practices which encourage abuse.

In Nigeria, it says, people traffickers often use traditional religion to cast spells which make their victims feel trapped and afraid.

And in Latin America, the use of children as domestic servants can also involve an assumption that such youngsters are sexually available to their employers.

Internet use

Ms Madrinan said that while quantifying commercial sexual exploitation of children is very difficult, there has been an increase in the number of arrests and international operations in the last few years and that images of abused children are more widely available on the internet.

"There is no better measurement of the growth of the exploitation of children than that," she said.

"It's one of the ways that enables us to quantify [the problem]."