Syrian children were used as human shields by government troops, according to a UN report.
In addition to the children being forced to ride on top of tanks to stop the attack by rebels, the children were also tortured in detention and slaughtered during the recent massacres, the BBC reported.
Radhika Coomaraswamy, the UN's Special Representative for Children and Armed Conflict, said: "Many former soldiers spoke about shooting into civilian areas, seeing children, young children, being killed and maimed."
Coomaraswamy said she had never seen such a situation, where even children were not spared and targeted in a conflict.
"We also had testimonies and saw children who had been tortured and who carried the torture marks with them. We also heard of children being used - this was recounted to us by some children - of being put on tanks and being used as human shields so that the tanks would not be fired upon," she added.
The UN report cited several cases of children being tortured, beaten with electric cables, burnt with cigarettes and even subjected to electric shock by pro-government forces.
"We are really quite shocked. Killing and maiming of children in cross-fire is something we come across in many conflicts but this torture of children in detention, children as young as 10, is something quite extraordinary, which we don't really see in other places," Coomaraswamy said.
The Free Syrian Army (FSA), the main opposition group against the Syrian regime, was equally to blame for endangering the lives of children, the report said.
Coomaraswamy also criticised the FSA for having recruited children for frontline jobs in areas such as medical care and service.