Terror threat

Islamic State group: The full story

Abu Anis only realised something unusual was happening when he heard the sound of explosions coming from the old city on the western bank of the Tigris as it runs through Mosul.

"I phoned some friends over there, and they said armed groups had taken over, some of them foreign, some Iraqis," the computer technician said. "The gunmen told them, 'We've come to get rid of the Iraqi army, and to help you.'"

The following day, the attackers crossed the river and took the other half of the city. The Iraqi army and police, who vastly outnumbered their assailants, broke and fled, officers first, many of the soldiers stripping off their uniforms as they joined a flood of panicked civilians.