Ten children were among 16 people killed in a Syrian government air strike that hit a bus in eastern Deir Ezzor province on Wednesday, a monitoring group said.
But state television said that the jihadist Islamic State group had killed the passengers, putting the death toll at 13 without specifying how they were killed.
The Syrian Observatory for Human Rights said 16 people were killed when a raid hit the bus as it travelled towards Damascus through the Shula area, which is under the control of the Islamic State.