Islamic State suicide bombers and fighters struck targets on Saturday in the northern Iraqi city of Samarra, where security forces and their Shi’ite militia allies have been gathering for an offensive against the radical Sunni militants.

Security sources and residents said the attack on Samarra was launched at 5.30 am (0230 GMT) when two Islamic State suicide bombers blew up their cars in the northern area of Sur Shnas.

At the same time a man drove a Humvee rigged with explosives into the south of the city and detonated it, while Islamic State fighters attacked security forces to the west with sniper fire, mortars and rocket-propelled grenades. […]