One in five homicide victims worldwide are children, a report by UN children's agency UNICEF has revealed.
The Hidden in Plain Sight report analyses data from from 190 countries and lists alarming statistics on child homicides, domestic violence and rape.
The report found violence against children was most common in the home and with caregivers.
UNICEF spokesman for Eastern and Southern Africa, James Elder, said the report may not even capture the full extent of the problem.
"Violence is a very difficult thing often to detect, it goes grossly unreported, so one of the terrifying things from this report is knowing that in fact the numbers would be lower than the reality," he said.
The UNICEF report found 120 million girls have been forced to have sex or perform sex acts before they turn 20.
Facts about violence against children
Source: UNICEF's Hidden in Plain Sight report
- In 2012, homicide took the lives of about 95,000 children and adolescents under the age of 20.
- Around 6 in 10 children between the ages of 2 and 14 worldwide subjected to physical punishment by caregivers on a regular basis.
- Close to 1 in 3 students between the ages of 13 and 15 report involvement in one or more physical fights in the past year.
- More than 1 in 3 students between the ages of 13 and 15 worldwide experience bullying on a regular basis.
- About 1 in 3 adolescents aged 11 to 15 in Europe and North America admit to having bullied others at school.
- Almost one quarter of girls aged 15 to 19 worldwide report being victims of some form of physical violence.
- Around 120 million girls under the age of 20 subjected to forced sexual intercourse or other forced sexual acts.
- 1 in 3 adolescent girls aged 15 to 19 have been the victims of any emotional, physical or sexual violence committed by their husbands or partners.
- About 3 in 10 adults worldwide believe physical punishment is necessary to properly raise or educate children.
- Close to half of all girls aged 15 to 19 think a husband is sometimes justified in hitting or beating his wife.
It also found in some countries, 80 per cent of adolescent girls believed it was acceptable for husbands to hit their wives.
"There really is a litany of very, very uncomfortable facts," Mr Elder said.
"No government or parent will want to see them."
It is worse for girls who have been married in their adolescence.
One in three of them - or 84 million - has been a victim of some form of violence by their husbands or partners.
The report says millions of children around the world also suffer at school.
One-in-three young teenage students report being bullied and the report shows child victims of violence will rarely seek help.
"What this report does clearly show is the prevalence of violence against children," Mr Elder said.
"We may not always see or hear about it, but unfortunately those most vulnerable are innocent and are victims of a fairly substantial amount of violence."
When it comes to the issue of violent discipline, about one third of adults believe physical punishment is necessary for children.
But Mr Elder is optimistic attitudes to children can be changed though, pointing to the way attitudes towards smoking have changed in Australia in the last 30 years.
He said Australia was a leader in terms of discussing child safety, but there are worrying trends.
"Often countries will have good policies in place - it's about implementing them," he said.
"That then comes down to the community level, that then comes down to the societal attitudes towards that, and that's a more longer term project."