Fighters from the Islamic State of Iraq and the Levant (ISIL) group have overrun one of the last remaining districts held by government forces in the Iraqi city of Ramadi, security officials have said.
Iraqi special forces soldiers fled as the armed group succeeded in breaching their last holdout.
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.
"We do not have an accurate count yet," said Muhannad Haimour, a spokesman for the governor of Anbar province on Monday. "We estimate that 500 people have been killed, both civilians and military, and approximately 8,000 have fled the city."
The estimates are since Friday, when the battle for the city reached its final stages. The 8,000 figure is in addition to the enormous exodus in April, Haimour said, when the U.N. said as many as 114,000 residents fled from Ramadi and surrounding villages at the height of the violence.
"Ramadi has fallen," said Haimour on Sunday. "The city was completely taken. ... The military is fleeing."
The armed group had earlier made significant gains in its battle to control Ramadi, besieging the army base and killing 15 soldiers in multiple suicide car bomb attacks.
Ramadi is the capital of Anbar, Iraq's largest province, and one of just a few towns and cities to have remained under government control.
On Sunday, Iraq's prime minister ordered his country's security forces not to abandon their positions in Anbar province to ISIL, as some troops left their weapons and vehicles behind to flee the fighters.
Prime Minister Haider al-Abadi also ordered Shiite militias to prepare to go into the Sunni-dominated region, ignoring worries their presence could spark sectarian bloodshed.
The involvement of Shia militias has been condemned by leading tribal figure Sheikh Ali al-Hatim, who said it would be considered an "Iranian occupation."
ISIL fighters had seized most of Ramadi, the capital of Anbar province, on Friday planting their flag on the local government headquarters in the center of the city, but a contingent of Iraqi special forces was holding out in the Malaab neighbourhood.
Security sources said those forces retreated on Sunday to an area east of the city after suffering high casualties.
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 ISIL fighters 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.
Al Jazeera and wire services