Iraqis fleeing the Old City of Mosul arrive in the industrial district of the city on June 23, 2017 (AFP Photo/MOHAMED EL-SHAHED)

Iraqis fleeing the Old City of Mosul are seen in the industrial district of the city on June 23, 2017 (AFP Photo/MOHAMED EL-SHAHED)

Iraqis fleeing the Old City of Mosul are seen on June 23, 2017 (AFP Photo/MOHAMED EL-SHAHED)

Iraqis fleeing the Old City of Mosul arrive in the industrial district of the city on June 23, 2017 (AFP Photo/MOHAMED EL-SHAHED)

Mosul (Iraq) (AFP) - They all say they are back from "hell". Quivering and emaciated, the civilians emerging from Mosul's Old City have survived famine but often lost relatives and sometimes their sanity.

They come in small groups, dropped off by the armoured vehicles of the Iraqi security forces on dusty, deserted streets where emergency field clinics are set up.

A few hundred metres away, fighting rages in the alleyways of old Mosul, where die-hard Islamic State group jihadists are mounting a desperate defence of their last redoubt in the city.

Elite Iraqi fighters backed by jets and special forces from a US-led anti-IS coalition massively outnumber and outgun the jihadists, who at this stage in the battle owe their survival to an estimated 100,000 civilians they are using as human shields.

With every home they retake, the security forces free families they often find holed up in their basements to shelter from the deluge of munitions that has been falling on the area since a push into the Old City was launched on June 18.

Adding to the constant threat of their homes collapsing over their heads from bombs, missiles or shells, IS has not hesitated to shoot down civilians to prevent them from fleeing.

Once their identity has been checked, rescued families are moved to a field clinic, where children devour the biscuits soldiers give them.

The adults, some of them with protruding bones and sunken eyes that speak of the famine they left behind, look shellshocked.

One woman wrapped in black lets out a hysterical, lonely howl of despair: "Too many innocents have been killed."

"We're back from the dead," says Amir, a 32-year-old man with a sickly grey complexion, shaking like a leaf between his sons Qusay and Hassan, aged two and four.

He shows a few crumbs in the bottom of a tin cup that he kept like it was a priceless treasure: "This is what we've been eating for weeks."

Umm Nashwan, a frail woman in her sixties, explains how she fed her family by mixing flour with water and baking the resulting dough.

She says she had only one obsession recently: "I just wanted to forget hunger".

- 'Take all my blood' -

"They live hidden in their basements and are almost starving to death," says one officer with the federal Iraqi forces. "Some of them resort to eating grass, others even eat dogs."

"Most IDPs (internally displaced persons) suffer from malnutrition and dehydration, kids above all," says Ahmed Diran, one of several volunteers at the emergency clinic.

"Adults often come in hysterical condition, crying and shouting, because nearly all of them have lost three to four family members," he says.

"It's getting worse and worse. And it may get very much worse because all civilians are now trapped with jihadists in a limited number of buildings, so more vulnerable," Diran explains.

The reception that rescued civilians get however is sometimes tainted by suspicion, with large sections of the Iraqi public arguing that whoever did not flee IS's brutal "caliphate" in three years was agreeable to it.

A suicide bomb attack by a jihadist who blended in with fleeing civilians on Friday and killed at least 12 people has only added to the tension.

An umpteenth humvee comes screeching to a halt to offload a young couple carrying a small inert body covered in blood.

The woman in a black abaya and pink veil collapses on a chair and shouts at the soldiers: "We've been waiting for you for months, what took you so long?"

The blood of her child, who was aged around six and killed by a stray bullet or a sniper a few blocks away, drips heavily down her arms.

"It's my only child, save him, I beg you. Take all my blood if you have to," she screams, banging her head against a wall.

The couple say they decided to risk being shot by IS to flee the Old City after two of their close relatives were killed by shelling.

The distressed mother recalls how happy her son was at the prospect. "He was hungry, he said: 'I want to say hello to the soldiers and get biscuits from them'."