The final battle to recapture Fallujah, Islamic State's stronghold near Baghdad, will start in "days, not weeks", a Shi'ite militia leader says, as new reports emerge of people starving to death in the besieged Sunni city.
The first phase of the offensive that started on Monday (local time) is nearly finished, with the complete encirclement of the city that lies 50km west of the Iraqi capital, said Hadi al-Amiri, leader of the Iranian-backed Badr Organization, on Friday.
Amiri, in military fatigues, spoke to state-TV from the operations area with Prime Minister Haider al-Abadi standing by his side, wearing the black uniform of Iraq's counter-terrorism force.
At the end of last year, Abadi said 2016 would be the year of the final victory over Islamic State, which declared a caliphate two years ago in territory it controls in Iraq and Syria.
Fallujah is a bastion of the insurgency that fought the US occupation of Iraq and the Shi'ite-led authorities that replaced Sunni leader Saddam Hussein.
It was the first city captured by Islamic State in Iraq, in January 2014, and is the second-largest still held by the militants after Mosul, their de-facto capital.
Amiri said this week the Shi'ite paramilitary coalition known as Popular Mobilisation would only take part in the encirclement operations, and would let the army storm Fallujah.
It would only enter the city if the army's attack failed.
The army has defused more than 250 explosive devices planted by the militants in roads and villages to delay the troops' advance, state TV said, citing military officers.
Amiri called on civilians to leave from a southwestern exit called the al-Salam (Peace) Junction.
But the United Nations said on Friday about 50,000 civilians were being prevented by the hardline Sunni militants from escaping.
Those who did manage to flee the city reported some people were dying of starvation, the UN refugee agency UNHCR said.
The Norwegian Refugee Council on Thursday reported similar accounts from displaced people interviewed at a camp near Fallujah.
"Food has been in very short supply. We are hearing accounts that people are relying on expired rice and dried dates and that's about it for their diet," UNHCR spokeswoman Melissa Fleming told a news briefing in Geneva.
Between 500 and 700 IS militants are in Fallujah, according to a US military estimate. The death toll since the start of the military operation on Monday has reached about 50, including 30 civilians and 20 militants, a source in the city's main hospital said.