Baghdad: Islamic State group fighters attacked Iraqi police and soldiers in an area considered a major staging ground for operations to reconquer Anbar province, security sources said.
IS fighters used suicide car bombs to attack government and allied forces in Khaldiyah, a town in the Euphrates valley that lies between Fallujah and Ramadi, Anbar's two main cities.
A police lieutenant colonel said IS fighters stormed the town's Al-Madiq neighbourhood "following clashes that forced army and federal police to abandon their positions."
"Local police and tribal fighters were left alone to fight Daesh in that area," he said, using an Arabic acronym for the group that took over large parts of Iraq last year.
"After entering Al-Madiq, the organisation deployed fighters with suicide vests in houses and streets," he said.
A spokesperson for Anbar tribes fighting alongside the government said federal security forces were attempting to regain the initiative.
"The aim of the operation is to regain control of Al-Madiq and kill the suicide attackers before they target security forces and tribal fighters," Sheikh Sufian al-Ithawi said.
In its daily online radio broadcast, IS said it had launched three suicide car bomb attacks in the Khaldiyah area.
It also claimed in a statement that it had killed tens of pro-government fighters and captured a brigadier general, although security officials gave no confirmation.
A senior police officer said IS fighters fired mortar rounds and rockets at security positions in Habbaniyah, although the attack seemed limited in scope.
The Habbaniyah area, further east, is home to the main base from which Iraqi forces are planning their promised reconquest of Anbar and where US advisers and trainers are stationed.
IS has controlled Fallujah since early 2014 and captured provincial capital Ramadi in May following a three-day blitz that dealt Baghdad its worst military setback in a year.
The government had to call in Iran-backed Shiite militias to contain the jihadist offensive and supplement its own under-performing forces.
Officials and military commanders have vowed to liberate the entire province but US elite forces faced the toughest battles of their eight-year occupation of Iraq in Anbar.
There also appears not be any consensus on whether anti-IS forces should first attack Ramadi or Fallujah, which is closer to Baghdad.