A suicide bomber blew himself up inside a bus travelling from the northern Iraqi city of Mosul to Syria on Tuesday, killing at least 40  passengers, an Iraqi army officer said.

Iraqi army Lieutenant Colonel Jalal Dosky said the attack took place near a checkpoint in an area called Smeirath, 80 km north of Mosul.

A senior Iraqi police officer in Mosul also confirmed the attack.

The United States military said in a statement that they suspected that an al Qaeda in Iraq (AQI) member carried out the attack but said eight people were killed in the bombing.