Syria's children are perhaps the greatest victims of their country's conflict, suffering "layers and layers of emotional trauma", Save the Children's chief executive told Reuters.

Syrian children have been shot at, tortured and raped during two years of unrest and civil war, the London-based international charity said in a report released on Wednesday.

Two million children, it said, face malnutrition, disease, early marriage and severe trauma, becoming innocent victims of a bloody conflict that has already claimed 70,000 lives.

"This is a war where women and children are the biggest casualty," chief executive Justin Forsyth told Reuters during a visit to Lebanon, where 340,000 Syrians have fled.