The battles in Anbar province, a mostly-Sunni desert region that shares a border with Syria, and a protracted surge in nationwide violence have left more than 850 people dead so far this month, fuelling fears Iraq is slipping back into the all-out conflict that plagued it in 2006 and 2007.

Security forces and allied tribal fighters on Wednesday regained control of Albu Farraj, just north of Ramadi, as well as a district on the outskirts of Fallujah, officials said.

"Iraqi security forces have taken control of Albu Farraj," said Defense Ministry spokesman Mohammed al-Askari, describing the area as an "important base" for militants, including the al-Qaeda-linked Islamic State of Iraq and the Levant (ISIL).

"We will give it back to the tribes and police forces to return the area to normal."

Officials said Iraqi forces also took back al-Nasaf, on the western outskirts of Fallujah, on Wednesday.

Security forces have been locked in deadly battles in Ramadi, where militants hold several neighborhoods, and have carried out operations in rural areas of Anbar province.

Anti-government militants also hold all of Fallujah, on Baghdad's doorstep.

ISIL has been involved in the fighting, and witnesses and tribal leaders in Fallujah say the group has tightened its grip on the city in recent days, but other militant groups have also taken part in the battles.

It is the first time militants have exercised such open control in Iraqi cities since the peak of violence that followed the 2003 US-led invasion.

The standoff has forced more than 140,000 people to flee their homes, the UN refugee agency said, describing this as the worst displacement in Iraq since its 2006-2008 sectarian conflict.

HH/HH