NEW DELHI: The Iraqi government has said that at least 322 members of the Al-Bu Nimr tribe -- dozens of whom are women are children -- have been killed by the Islamic State (IS) the past week in Iraq’s western Anbar province.

The Al-Bu Nimr tribe had been resisting the IS’ advance till they ran out of fuel and ammunition. On Sunday, at least 75 members of the tribe were killed when they were caught trying to escape the militant group, their bodies found dumped near the town of Haditha.

“The number of people killed by Islamic State from Al-Bu 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.

The news follows reports that more than 200 members of the Al-Bu Nimr tribe were slaughtered by the militants on Thursday. The bodies of 150 Al Bu Nimr tribesmen were found in a mass grave near Ramadi in Anbar and in a separate incident, more than 70 Al-Bu Nimr men were found in a mass grave near the town of Hit.

Reuters quoted locals saying that IS militants had offered the tribesmen a safe passage to move to Zauiyat Al-Bu Nimr, the tribe’s main village, but intercepted them and executed them along the way.

Earlier last week, in another brutal incident, IS militants rounded up at least 40 Sunni tribal fighters and security force personnel, who had fought against the group in Hit, parading them in the streets before shooting and killing them in a public execution in front of local residents at the city’s central square.

The public execution was the first of its kind in Anbar province, where the militants have been gaining ground steadily. A week ago, the group captured Albu Nimr area in the province, prompting warnings that the entire province -- that borders Jordan, Saudi Arabia and the Baghdad province -- could soon fall to the militants.

Reports of these executions and killings targeting Sunni tribesmen who have resisted IS, is likely to further dampen resolve among Sunni arabs to fight the militant group. The Iraqi government has been trying to enlist tribal councils to resist the IS advance, and these incidents -- exacerbated by claims that the Iraqi government has been slow in responding to the tribals’ demands -- will only fuel distrust of the Shia-dominated administration at the centre.

US airstrikes hit IS targets in Iraq over the weekend, specifically near the cities of Baiji, north of Baghdad and Falluja, in Anbar province. These strikes do not yet seem to have impacted the IS’ advance into Anbar province.

In a separate incident, three car bombs attacking Shi’ite pilgrims in Baghdad killed at least 34 people on Sunday, deepening the country’s sectarian crisis. A few days ago a suicide bomber killed 27 Shi’ite militiamen on the outskirts of the Iraqi town of Jurf al-Sakhar -- which in turn was in the news as security forces pushed back IS militants to regain the town.

Meanwhile, fighting continues in the Syrian-Turkish border town of Kobani, which has been besieged by IS for over a month. The United States launched more airstrikes over the town this weekend as peshmerga forces from Iraq crossed the border to join Kurdish fighters battling the militants.