Human Rights Watch on Monday urged Syria militant groups to stop enlisting children in their ranks and warned their foreign backers that they could be implicated in "war crimes".

Human Rights Watch on Monday urged Syria militant groups to stop enlisting children in their ranks and warned their foreign backers that they could be implicated in "war crimes".

 The New York-based rights watchdog accused militant groups of using "children as young as 15 to fight in battles" against the Syrian army and citizens.

Radicals in Syria, including the powerful 'jihadist' group the Islamic State of Iraq and the Levant (ISIL) "have specifically recruited children through free schooling campaigns that include weapons training, and have given them dangerous tasks, including suicide bombing missions", AFP reports.

The HRW report was based on the experiences of 25 child soldiers - some of whom are still fighting - who were involved in ISIL, the Free Syrian Army (FSA), the Islamic Front, Syria's Al-Qaeda affiliate the Al-Nusra Front and other terrorist groups.

The children interviewed by HRW said they took part in combat, worked as snipers, manned checkpoints, spied, cared for the wounded, or carried munitions or other supplies to the front line. Many said they had joined up to follow friends or family.

"Syrian militant groups shouldn't prey on vulnerable children by enlisting them in their forces," HRW's Priyanka Motaparthy said.

HRW also urged countries supporting the terrorist groups to press for an end to child recruitment. "Governments supporting militant groups in Syria need to press these forces to end child recruitment and use of children in combat," Motaparthy said. "Anyone providing funding for sending children to war could be complicit in war crimes."