BAGHDAD (AP) — More than 140,000 Iraqis have fled parts of Anbar province over clashes between security forces and al-Qaida militants, the worst displacement of civilians in years, a United Nations official said Friday.

The spokesman for the U.N. High Commissioner for Refugees, Peter Kessler, described it as "the largest" displacement witnessed in the country since the sectarian violence of 2006-2008. He added that more than 65,000 people fled the conflict just in the past week alone.

Since late December, members of Iraq's al-Qaida branch — known as the Islamic State of Iraq and the Levant — have taken over parts of Ramadi, the capital of the largely Sunni province of Anbar. They also control the center of the nearby city of Fallujah.

Kessler said that many civilians are trapped and suffer from a lack of supplies.

"Many civilians are unable to leave conflict-affected areas where food and fuel are now in short supply," he said.

Calls to Iraq's Justice Ministry over the report rang unanswered Friday, the start of the weekend in the Muslim world.

Some displaced families have ended up in abandoned buildings, schools and half-built houses while others stay with relatives. International aid agencies appealed to the warring parties on Wednesday to allow humanitarian aid to reach those affected.

Farhan Haq, a spokesman for U.N. Secretary-General Ban Ki-moon, said Friday that the world body asked the Iraqi government to open a "humanitarian corridor" to help aid get into affected areas.

"It's impossible right now to reach the area from Baghdad, and relief agencies are using roads coming from northern Iraq," Haq said.

As sporadic clashes resumed Friday night in Fallujah, a mortar shell landed on a house in the city's center, killing six people, including an 8-year-old boy, local doctor Waisam al-Mohammadi said.

Political and sectarian tensions are running high in Iraq, raising fears that the country is being pushed back toward the sectarian bloodshed that killed tens of thousands of people following the 2003 U.S.-led invasion that ousted Saddam Hussein.

___

Associated Press writer Cara Anna at the United Nations contributed to this report.