A report by the United Nations refugees agency says many children who have fled the conflict in Syria are psychologically traumatised by their experience of war.
More than half the 2.2 million registered refugees from Syria are children, the UN High Commission for Refugees said.
As many as 300,000 living in Lebanon and Jordan could be without schooling by the end of 2013 and many of those not at school go out to work for long hours and for low pay from as young as seven years old.
The report's authors said many face grave dangers even outside the war zone, including threats to their physical and psychological well-being.
They found high levels of child recruitment, labour and loneliness among children living in displaced families.
More than 70,000 Syrian refugee families now live without fathers, the UNHCR estimates, with some 3,700 refugee children living unaccompanied or without both parents.
The study comes shortly after an estimate from a London-based think-tank put the number of children killed during Syria's civil war at more than 11,000, the BBC reports.
The UNHCR carried out a series of interviews with Syrian children and families living in Jordan and Lebanon between July and October 2013.
Researchers interviewed 81 refugee children and held group discussions with 121 others in Jordan and Lebanon, and consulted UN and NGO staff working with those communities.