Last Updated May 17, 2015 6:40 PM EDT
BAGHDAD - The contested city of Ramadi fell to the Islamic State of Iraq and Syria (ISIS) on Sunday, as Iraqi forces abandoned their weapons and armored vehicles to flee the provincial capital in a major loss despite intensified U.S.-led airstrikes.
Bodies, some burned, littered the streets as local officials reported the militants carried out mass killings of Iraqi security forces and civilians. Online video showed Humvees, trucks and other equipment speeding out of Ramadi, with soldiers gripping onto their sides.
"Ramadi has fallen," said Muhannad Haimour, a spokesman for the governor of Anbar province. "The city was completely taken. ... The military is fleeing."
With defeat looming, Prime Minister Haider al-Abadi ordered security forces not to abandon their posts across Anbar province, apparently fearing the extremists could capture the entire desert region that saw intense fighting after the 2003 U.S.-led invasion to topple dictator Saddam Hussein.
Sunday's retreat recalled the collapse of Iraqi security forces last summer in the face of the Islamic State group's blitz into Iraq that saw it capture a third of the country, where it has declared a caliphate, or Islamic State. It also calls into question the Obama administration's hopes of relying solely on airstrikes to support the Iraqi forces in expelling the extremists.
Earlier Sunday, al-Abadi ordered Shiite militias to prepare to go into the Sunni-dominated province, ignoring U.S. concerns their presence could spark sectarian bloodshed. By late Sunday, a large number of Shiite militiamen had arrived at a military base near Ramadi, apparently to participate in a possible counter-offensive, said the head of the Anbar provincial council, Sabah Karhout.
"We welcome any group, including Shiite militias, to come and help us in liberating the city from the militants. What happened today is a big loss caused by lack of good planning by the military," a Sunni tribal leader, Naeem al-Gauoud, told the Associated Press.
He said many tribal fighters died trying to defend the city, and bodies, some charred, were strewn in the streets, while others had been thrown in the Euphrates River. Ramadi mayor Dalaf al-Kubaisi said that more than 250 civilians and security forces were killed over the past two days, including dozens of police and other government supporters shot dead in the streets or their homes, along with their wives, children and other family members.
The U.S.-led coalition said Sunday it conducted seven airstrikes in Ramadi in the last 24 hours. "It is a fluid and contested battlefield," said Army Col. Steve Warren, a Pentagon spokesman. "We are supporting (the Iraqis) with air power."
The final push by the extremists began early Sunday with four nearly simultaneous bombings that targeted police officers defending the Malaab district in southern Ramadi, a pocket of the city still under Iraqi government control, killing at least 10 police and wounding 15, authorities said. Among the dead was Col. Muthana al-Jabri, the chief of the Malaab police station, they said.
Later, three suicide bombers drove their explosive-laden cars into the gate of the Anbar Operation Command, the military headquarters for the province, killing at least five soldiers and wounding 12, authorities said.
Fierce clashes erupted between security forces and ISIS militants following the attacks, and the extremists later seized Malaab after government forces withdrew, with the militants saying they controlled the military headquarters.
A police officer who was stationed at the headquarters said retreating Iraqi forces left behind about 30 army vehicles and weapons that included artillery and assault rifles. He said some two dozen police officers went missing during the fighting.
The officer and other officials spoke on condition of anonymity as they weren't authorized to talk to journalists.
On a militant website frequented by Islamic State members, a message from the group claimed its fighters held the 8th Brigade army base, as well as tanks and missile launchers left behind by fleeing soldiers. The message could not be independently verified by the AP, but it was similar to others released by the group and was spread online by known supporters of the extremists.
Last week, the militants swept through Ramadi, seizing the main government headquarters and other key parts of the city. It marked a major setback for the Iraqi government's efforts to drive the militants out of areas they seized last year. Previous estimates suggested ISIS held at least 65 percent of the vast Anbar province.
On Friday, with Ramadi on the brink of collapse, the U.S. military command downplayed ISIS gains there, describing them as fleeting.
"We've seen similar attacks in Ramadi over the last several months which the (Iraqi security forces) have been able to repel," said Marine Brig. Gen. Thomas D. Weidley, chief of staff for the campaign fighting the militants, adding that the U.S. was confident the Iraqi government will be able to take back the terrain it lost in Ramadi.
Backed by U.S.-led airstrikes, Iraqi forces and Kurdish fighters have made gains against ISIS, including capturing the northern city of Tikrit. But progress has been slow in Anbar, a Sunni province where anger at the Shiite-led government runs deep and where U.S. forces struggled for years to beat back a potent insurgency. American soldiers fought some of their bloodiest battles since Vietnam on the streets of Ramadi and Fallujah.
U.S. troops were able to improve security in the province starting in 2006 when powerful tribes and former militants turned against al-Qaida in Iraq, a precursor to the Islamic State group, and allied with the Americans.
But the so-called Sunni Awakening movement waned in the years after U.S. troops withdrew at the end of 2011, with the fighters complaining of neglect and distrust from the Shiite-led government in Baghdad.