CNN  — 

At the age of just four, Satabraq finds soldiers and rockets more normal than classrooms and schoolmates.

Satabraq meanders the alleyways in the Old City of Mosul, a place that is both her home and a frontline. Dressed in red floral pajamas, she is led by Iraqi troops who laugh and play with her between firing mortar rounds.

“The first environment she has ever been exposed to is the police. She loves them more than she would students in a school,” Abdullah, her father, said. “She plays with them and they bring her sweets.”

Satabraq’s family is among the estimated 400,000 civilians, about a quarter of Mosul’s pre-war population, trapped in the Old City, according to the United Nations.

The densely populated historic center of Iraq’s third largest city once bustled with life, but now most streets are quiet, spectral.

“Civilians in Mosul face incredible, terrifying risks,” Lise Grande, the UN’s humanitarian coordinator for Iraq, said this week.

“They are being shot at, there are artillery barrages, families are running out of supplies, medicines are scarce and water is cut off. Nothing is more important than protecting civilians – nothing.”

Trapped by ISIS

Satabraq’s family sits near an Iraqi federal police firing position, making their home an obvious target for ISIS – a reality that either doesn’t bother or doesn’t occur to the girl’s father.

The alleyway is ringing with the constant cacophony of war. Satabraq’s disabled grandfather sits in a wheelchair sporting wrap-around shades, holding an old ice cream tub of his medication and wearing an indifferent expression.

“She was supposed to go to school but she couldn’t under ISIS, so she has trouble speaking,” Abdullah said. “There was nothing for her, no education, nothing. ISIS came, we shut our doors, and she was never allowed out.”

The brutal fight for Mosul

At the center of the Old City’s winding streets is al-Nuri Mosque, the ideological heart of ISIS in Iraq.

In 2014, Abu Bakr al-Baghdadi stood on its 12th century pulpit and announced the creation of the so-called Islamic caliphate. It was the first and last time the leader of the terrorist group spoke publicly to his followers.

Now, on the mosque’s famed leaning minaret, the black and white ISIS flag still flutt