With his security strategy in tatters and his authority facing its biggest challenge since he took office eight months ago, Prime Minister Haider al-Abadi was looking for quick redemption.
Reeling from the worst setback since IS grabbed swathes of territory in June last year, he called in the Shiite-dominated Popular Mobilisation units (Hashed al-Shaabi).
"The Hashed have started to arrive in areas east of Ramadi," said army Brigadier General Ali al-Majidi, speaking to AFP from a base west of Baghdad.
Abadi and Washington had hoped to rely on regular forces and locally recruited Sunni tribal fighters newly incorporated into the Hashed al-Shaabi to fight IS in Anbar.
More From This Section
Such a solution was seen as more palatable to the predominantly Sunni population of the province, and a way for Washington to keep Iranian-backed militias at bay.
The Shiite paramilitary groups had been eager to join the Ramadi battle for some time and argued that Abadi's reluctance led to the provincial capital's fall.
"The US government and Iraqi government seem to be on the same sheet of music that Ramadi has to be counterattacked before IS consolidates," Michael Knights of the Washington Institute said.
US Secretary of State John Kerry said yesterday he was "absolutely confident" that the situation could be reversed within days.
Anbar police chief Kadhim al-Fahdawi said a large number of well-prepared troops were positioned in Husaybah, about seven kilometres (less than five miles) east of Ramadi.
But much planning remains to be done before Iraqi forces attempt to move back into Ramadi, a large town on the Euphrates about 100 kilometres west of Baghdad.