NORTHERN SYRIA -- As ISIS faces defeat in Raqqa, a group Syrian men have volunteered to finish them off. The new recruits learned to detect explosives on roads, inside houses and detonated via remote control.

After just 15 days of training, they'll head straight for the frontline.

America's closest allies on the ground in Syria are shopkeepers, truck drivers, tailors and construction workers. CBS News correspondent Holly Williams asked them how many had lost family members to ISIS; They all raised their hands.

Ahmed Shahata, right, and other Syrian recruits CBS News

"They've killed my relatives, cousins and neighbors," said Ahmed Shahata, who was a butcher until he signed up.

They're driven by revenge, and hungry for American help. U.S. special operations soldiers oversee the training, but don't want to show their faces.

Without American airstrikes, defeating ISIS would have been near impossible, but some of those now escaping ISIS territory say it's the strikes that are their biggest fear. The U.S. coalition admits that more than 700 civilians have been inadvertently killed in Syria and Iraq; others claim the number is far higher.

ISIS mutilated recruit Renas Halep CBS News

For Renas Halep, though, anyone who wants to destroy ISIS is a friend. He told Williams ISIS falsely accused him of stealing, and amputated his hand four years ago. It's a punishment the extremists have used extensively.

"Why do you think they wanted to do this to you?" Williams asked him.

"They want to terrify people," he said, "so they can rule them."

U.S.-backed forces say more than 350 civilians have managed to escape Raqqa in the last three days as they close in on ISIS. But that could still leave more than 1,000 people trapped in the city.