Iraq crisis: Kurd forces 'advance' on Mosul dam
17 August 2014 Last updated at 10:44 BST
Kurdish sources say their forces "are advancing" in an offensive to retake Mosul dam from the Islamic State (IS) jihadist group.
A joint operation involving both Kurdish forces and US air strikes has been under way since 05:00 local time (03:00 GMT), the sources said.
The strategic dam, which supplies water and electricity to northern Iraq, was seized by the militants on 7 August.
The BBC's Jim Muir in Irbil, in Iraqi Kurdistan, said there was hope that the militants would be induced to leave the dam by the threat of extreme force.