The systematic killings, which one tribal leader said were continuing on Sunday, marked some of the worst bloodshed in Iraq since the ISIS terrorists swept through the north in June with the aim of establishing "medieval caliphate" there and in Syria.
The Albu Nimr, also Sunni, had put up fierce resistance against ISIS for weeks but finally ran low on ammunition, food and fuel last week as ISIS fighters closed in on their village Zauiyat Albu Nimr.
"The number of people killed by ISIS from Albu Nimr tribe is 322. The bodies of 50 women and children have also been discovered dumped in a well," the country's Human Rights Ministry said on Sunday.
State television said on Sunday that Prime Minister Haider al-Abadi had ordered airstrikes on ISIS targets around the town of Hit in response to the killings.Iraq's most senior Shi'ite cleric, Grand Ayatollah Ali al-Sistani, called on the government on Friday to rush to the aid of Sunni tribal leaders.
Video released by Iraqi defense ministry shows Iraqi warplane targeting ISIS position in town of Hit in Anbar province. Also Iraqi army attack terrorist in this province.
ISIS already controls most of the vast desert province which includes towns in the Euphrates River valley dominated by Sunni tribes, running from the Syrian border to the western outskirts of Baghdad.
If the province falls, it could give ISIS a better chance to make good on its threat to march on the capital.
Ga'aud said 75 more members of his tribe were killed on Sunday under the same scenario -- they were hunted down while trying to escape from ISIS, shot dead execution-style and dumped near the town of Haditha.
The Albu Nimr leader also said ISIS killed 15 high school and college students in Zauiyat Albu Nimr and that, apart from an air drop, there had been no help from the U.S.-led air campaign.
In Anbar, the militants are now encircling a large air base and the vital Haditha dam on the Euphrates. Fighters control towns from the Syrian border to parts of provincial capital Ramadi and into the lush irrigated areas near Baghdad.