The BBC has seen evidence that so-called Islamic State (IS) has been using children as human shields as they fight to keep control of the Iraqi city of Mosul. BBC Persian correspondent Nafiseh Kohnavard and producer Joe Inwood had exclusive access to helicopter missions of the Iraqi military and witnessed the battle from above.
Erij Military camp is a dusty compound just a few miles south of Mosul. The mangled and melted gas tanks that rise in the background hint at violent battles in the recent past. Giant attack helicopters sit on the tarmac, their sleek fronts give them an aggressive look, ready for action.
They never have to wait long.
Within minutes of our arrival, two young men in their flight suits run to their helicopter. The ground crew spring into action and within moments they are in the air. Their destination is west Mosul, the newest front in the battle against IS.
We spent more than a week living at the base, flying with the pilots who have helped in the battle against the militants who have ruled Mosul for two years.
It is not the first time that we have followed Iraq's helicopters as they battle IS: at Sinjar as they delivered aid to refugees trapped on the mountain; over the factory in Mishraq that doubled as a training camp for suicide bombers; last summer in the bloody fight for Falluja.
But, somehow, this time felt different. General Samir Hussain, the man in charge of the mission, confirmed our suspicions.
"Mosul is the toughest job we have ever had. There is no comparison with any other mission that you have witnessed."
It should not be surprising. For the first time, the pilots are operating above a city where tens, maybe hundreds of thousands of civilians are trapped. And, unlike Falluja, the militants are encircled. They have no prospect of escape or chance of a military victory. And so they turn the people of Mosul into human shields.
As we sit having tea one morning, we see a familiar face. With his smiling eyes and toothy grin, Colonel Mohammed is a popular figure amongst the Iraqi army. He is also one of their most experienced pilots. We last saw him flying over Falluja.
He joins us for a green tea, and describes a scene he recently witnessed in old Mosul. The smile flickers from his face as he recalls it. An IS sniper had shot a woman in the street. She was being used as bait to lure federal police into his cross hairs. Col Mohammed was called in for air support.