AKIPRESS.COM - Islamic State militants have executed 85 more members of the Albu Nimr tribe in Iraq in a mass killing campaign launched last week in retaliation for resistance to the group's territorial advances, Reuters reported referring to a tribal leader and security official.

Sheikh Naeem al-Ga'oud, one of the tribe's leaders, said that Islamic State killed 50 displaced members of Albu Nimr on Friday. In a separate incident, a security official said 35 bodies were found in a mass grave.

The sustained bloodshed shows how the al-Qaeda offshoot has proven resilient despite U.S. airstrikes against militant targets in parts of Iraq and Syria it controls.

Members of the Albu Nimr tribe had held out for weeks under siege by Islamic State fighters in Anbar Province to the west of Baghdad, but finally ran low on ammunition, fuel and food.

Hundreds of tribal fighters withdrew and hundreds of members of the tribe fled their village. Islamic State rounded many up and shot them at close range.

Over 300 people have been executed since the killing began in the middle of last week.