Children from the village of Adla south of Mosul, who claim to have recently escaped the extremist group’s clutches, say the militants are killing anyone who tries to flee and brainwashing local children to carry out suicide attacks.

Ahmed, 15, said that he had been trained by ISIL militants in combat techniques, weapons use and bomb-planting.

"We were trained [by ISIL] in our village," Ahmed -- who gave only his first name due to fears of reprisal -- said.

"We did what we were told, fearing for our safety and for that of our families," he added.

Jassim, another young Adla resident (who did not provide his age), said the militants had trained him on how to carry out suicide attacks.

"They wanted to use us as suicide bombers in their dirty wars," he said. "They told us we would be martyrs; that after we died we would to heaven."

ISIL captured Mosul -- along with the city’s outlying villages -- in mid-2014 before overrunning large swathes of territory in the country’s northern and western regions. 

On Sunday night, Iraqi forces, backed by U.S.-led coalition airstrikes, launched a much-anticipated offensive to retake the city -- ISIL’s last stronghold in northern Iraq. 

Over the last five days, the extremist group has lost numerous villages on Mosul’s outskirts, as the Iraqi army and its allies advance on the city along multiple axes.