Iraq government on Monday ordered Iran-backed Shiite paramilitary forces to mount a counter-offensive in the predominantly Sunni Anbar province, to help retake the provincial capital Ramadi, after marauding Islamic State militants killed an estimated 500 Iraqi civilians and soldiers and forced 8,000 people to flee from their homes.
Nearly 3,000 Shiite fighters from the so-called Popular Mobilization Units had arrived at the Habanniya military base, 16 miles east of the provincial capital Ramadi, Anbar's provincial council said.
They were ''well-equipped'' to fight alongside local Sunni tribesman, according to a statement.
Reports say hundreds of people are still trapped on the outskirts of Ramadi, after the fighters of the Islamic State of Iraq and the Levant, blocked escape routes and left little food for those remaining in the Khalidiya and Hasbanniya districts outside the city.
The fall of Ramadi, the group's most significant victory since it seized Mosul and other northwestern cities last June, comes less than two months after the Iraqi army and militias, backed by US air power, ousted ISIS from the city of Tikrit.
Iraq's government and Iranian-backed Shiite militias vowed to mount a counter-offensive and reclaim Ramadi.
Iran's defence minister GenHossein Dehghan also flew to Baghdad on a surprise visit for urgent talks with Iraqi leaders.
''The popular forces are expected to bring battlefield skills that the local police and units don't have,'' a government official said, referring to the militias. ''They know how to face Daesh with the same guerrilla tactics that Daesh uses,'' the minister said.
The Shiite militias in the force have already started launching attacks on Ramadi in a bid to restore government control over the city and prevent Islamic State forces from advancing east toward the Iraqi capital, Baghdad, or south toward Shiite holy sites.
A defeat in Ramadi could strengthen the ISIS resolve and handicap the Iraqi government's strategy for defeating Islamic State.
Prime Minister Haider al-Abadi last month announced a major offensive in Anbar, the country's largest province. He also pledged to strengthen local Sunni tribesmen to reinforce regular security forces and to cut Islamic State supply routes from Ramadi to the Syrian border.
US and some Iraqi officials fear Shiite militias, now Iraq's most effective fighting force, can work with Sunni forces and tribesmen in the fight against Islamic State.
Separately, American officials also fear that the militias could inadvertently get caught in US-led airstrikes if not effectively controlled by the government.