Violence in parts of Anbar province held by anti-government militiamen killed three people as the United Nations warned Friday of Iraq’s worst displacement since its brutal 2006-08 sectarian conflict.

Violence in parts of Anbar province held by anti-government militiamen killed three people as the United Nations warned Friday of Iraq's worst displacement since its brutal 2006-08 sectarian conflict.

More than 65,000 people have fled fighting in the Iraqi cities of Fallujah and Ramadi during the past week, the UN refugee agency UNHCR said on Friday, with more than 140,000 have been made homeless since fighting broke out at the end of last year, Reuters quoted UNHCR spokesman Adrian Edwards as saying.

Security forces and their tribal allies have been locked in a deadly standoff with militia groups including those affiliated with the Al-Qaeda-linked Islamic State of Iraq and the Levant (ISIL) terrorist organization.

National army has mounted a massive operation to retake parts of the Anbar provincial capital Ramadi held by anti-government gunmen, and for days have engaged in clashes and exchanged mortar fire.

Shelling which began early Friday of the Ramadi neighborhoods of Malaab and Albu Faraj, both out of the government's control, killed two people and wounded 30, security and medical officials said.

Government forces and militants also engaged in firefights in Ramadi on Thursday evening, but no casualties were reported. But one person was killed and seven wounded in heavy shelling late on Thursday in Fallujah, a former insurgent bastion also west of Baghdad that is entirely held by militants.

Parts of Ramadi and all of Fallujah have for weeks been in the hands of anti-government militiamen, including members of ISIL.