BAGHDAD -- Islamic State group extremists lined up and shot dead at least 50 tribesmen and women in Iraq's Anbar province, officials said Saturday, the latest mass killing committed by the group.

The shooting happened late Friday in the village of Ras al-Maa, north of the provincial capital of Ramadi, Anbar councilman Faleh al-Issawi said.

Militants accused men and women of the Al Bu Nimr tribe of retaliating against them after being displaced from their homes when the group seized the Anbar town of Hit last month, al-Issawi said.

"These killings are taking place almost on a daily basis now in the areas under the control of the Islamic State group and they will continue unless this terrorist group is stopped," al-Issawi told The Associated Press.

An official in the Anbar governor's office confirmed the death toll. He spoke on condition of anonymity as he is not authorized to brief journalists.

On Thursday, authorities found the bodies of 48 Sunni tribesmen killed by the Islamic State group in Anbar.

The Islamic State group has overrun a large part of Anbar province in its push to expand its territory, which currently current stands at about one-third of both Iraq and Syria. Officials with the Iraqi government, as well as officials with the U.S.-led coalition targeting the extremists, repeatedly have said that Iraqi tribes are key in the fight against the Islamic State group since they are able to penetrate areas inaccessible to airstrikes and ground forces.

Meanwhile Saturday, the United Nations mission in Baghdad said that at least 1,273 Iraqis were killed in violence in October, a slight increase compared to last month amid the Islamic State group's assault.

The UN report said violence killed 856 civilians and 417 members of Iraq's security forces, while attacks wounded 2,010 Iraqis.

The worst-hit city was Baghdad, with 379 civilians killed, the report said.

The UN figures do not take into account causalities in Anbar province nor some other militant-held parts of Iraq.

The UN has said September's death toll was 1,119 Iraqis killed.