The front line for militias battling Islamic State
25 May 2015 Last updated at 23:11 BST
Earlier this month militants from Islamic State seized the Iraqi city of Ramadi.
Its fall was seen as a major capitulation by the Iraqi Army in the strategically important Anbar province.
Since then, Iraqi government forces, backed by Shia militias, have been mobilising there.
The BBC's World Affairs Editor John Simpson travelled with a group of Shia militias to the town of Garma, in Anbar.