Islamic State militants are thought to have killed up to 500 people – both Iraqi civilians and soldiers – and forced 8,000 to flee from their homes as they captured the city of Ramadi.
The government-backed Shia militias have vowed to mount a counter-offensive and reclaim the Anbar provincial capital.
The statements followed Sunday’s shocking defeat of Iraq’s security and military forces as the militants swiftly took control of Ramadi, sending government forces fleeing in a major loss despite the support of US-led air strikes targeting the extremists.
Bodies, some burned, littered the city’s streets as local officials reported the militants carried out mass killings of Iraqi security forces and civilians. Online video showed vehicles, trucks and other equipment speeding out of Ramadi, with soldiers desperate to reach safety gripping on to their sides.
“We do not have an accurate count yet,” said an Anbar spokesman, Muhannad Haimour. “We estimate that 500 people have been killed, both civilians and military, and approximately 8,000 have fled the city.” IS militants have previously killed hundreds of civilians and soldiers in the aftermath of major victories.
The estimates given by Mr Haimour are for the past three days, since Friday, when the battle for the city entered its final stages. The 8,000 figure is in addition to the enormous exodus in April, Mr Haimour said, when the UN said as many as 114,000 residents fled Ramadi and surrounding villages at the height of the violence.
Sunday’s defeat recalled the collapse of Iraqi forces last summer in the face of a blitz by the extremist group across much of northern and western Iraq. Later, IS declared a caliphate in areas under its control in Iraq and neighbouring Syria.
Backed by air strikes from a US-led coalition since August, Iraqi forces and allied militias have recaptured some of the areas seized by IS in the past year, but the latest defeat in Anbar calls into question the Obama administration’s hopes of relying solely on air power to support Iraqi forces.
With defeat looming over the weekend, Shia prime minister Haider al-Abadi ordered security forces not to abandon their posts across Anbar, apparently fearing the extremists could capture the entire desert region that saw some of the most intense fighting after the 2003 US-led invasion to topple dictator Saddam Hussein. The militants are believed to be in control of more than 60 per cent of Anbar, which stretches from Baghdad all the way to Syria and Jordan.
Youssef al-Kilabi, a spokesman for the Shia militias fighting alongside government forces, said that the Iranian-backed paramilitary forces have drawn up plans for a Ramadi counter-offensive in co-operation with government forces. “We will eliminate this barbaric enemy”, Mr al-Kilabi vowed.
“God willing, we will achieve this triumph and we will not accept anything less than that.” He did not elaborate on the plans or timing of a counter-offensive.
Since IS blitzed through northern and western Iraq last June, thousands of Shia militiamen have answered the call from the country’s top Shia cleric, Grand Ayatollah Ali al-Sistani, to take up the fight against the militants. However, the Shia militias have been criticised in Iraq and abroad over charges of extrajudicial killings of Sunnis and looting of Sunni property.