CHILDREN as young as 11 are being beheaded in Mozambique, UK-based aid group Save the Children said yesterday, as part of an Islamist insurgency that has killed thousands and forced many magnitudes more from their homes. Save the Children said it had spoken to displaced families who described "horrifying scenes" of murder, including mothers whose young sons were killed. In one case, the woman hid, helpless, with her three other children as her 12-year-old was murdered nearby. "We tried to escape to the woods, but they took my eldest son and beheaded him," the 28-year-old, who Save the Children called…