Shi'ite fighters are preparing to launch a counter-assault on Anbar province after Islamic State militants reportedly took control of Ramadi.
A spokesman for the Shi'ite paramilitaries - known as Hashid Shaabi - told Reuters they had received instructions to mobilise, but details of the timing and scale of the deployment could not be revealed for security reasons.
Now that the Hashid has received the order to march forth, they will definitely take part.
They were waiting for this order and now they have it.
Ramadi is a Sunni Muslim-dominated area and Iraq's prime minister has previously resisted sending Shia militias into the area in the fear of sparking a sectarian backlash.
About 500 people - including civilians and Iraqi troops - are reported to have died over the last few days after Islamic State militants reportedly seized the city of Ramadi.
Islamic State said it had taken full control of the city yesterday, but US security officials insisted the situation was still "fluid and contested".
A spokesperson for governor of Iraq's Anbar province said that around 8,000 people had also fled the violence.
If Islamic State's gain is confirmed, it would mark the biggest victory for the terror group since security forces - aided by US-led air strikes - pushed them back last year.
The US is monitoring reports of continuing fighting in the western Iraq city of Ramadi, a spokesperson from the Pentagon has said.
The situation in the region is "fluid and contested", Maureen Schumann said, despite Islamic State claims that they had seized full control.
It is too early to make definitive statements about the situation on the ground there at this time.
Islamic State militants have taken full control of the Iraqi city of Ramadi, according to reports.
"Ramadi has fallen," Muhannad Haimour, a spokesman for the governor of Anbar province, is quoted as saying by the Associated Press.
"The city was completely taken. ... It was a gradual deterioration. The military is fleeing."
Earlier, an Islamic State message claimed the group had seized the city after Iraqi forces fled.
The Iraqi prime minister had made a desperate appeal to his forces not to abandon their posts amid the group's advance.
The Iraqi prime minister has urged his country's security forces not to abandon their positions in Anbar province to Islamic State as the militant group advanced.
The warning comes amid reports IS militants had driven troops from a key military base in the province.
Troops reportedly discarded their weapons and vehicles behind to flee Anbar Operations Command after the militants apparently promised them safety if they left their positions.
It is unconfirmed whether Iraqi forces still controlled Ramadi, the capital of Anbar, after Islamic State made significant gains in recent days.
In a state television address, Prime Minister Haider al-Abadi told Shiite fighters to be prepared to enter the mainly Sunni province to wrestle back control.
US mum Samantha Johnston has reportedly left her family in North Carolina to take up arms against so-called Islamic State militants in Iraq.Read the full story ›
Islamic State militants have withdrawn from the main government building in the Iraqi city of Ramadi, the mayor and tribal leader of the city has said.
The withdrawal comes just a day after the militant group's black flag was raised over the city.
Reports suggest that the local government compound has been captured in the western city.Read the full story ›
Islamic State (IS) militants staged a prison break in Iraq in which 50 inmates and a dozen policemen were killed, said two Iraqi officials.
"ISIS was responsible for the killings and the release of ISIS prisoners," said Oudi Al-Khadran, mayor of the town where the prison, which holds hundreds of people convicted of acts of terrorism, is located.
That account was confirmed to Reuters by Colonel Ahmed al-Timimi of the Diyala province security operations centre.