RAQQA, Syria -- There's been no official declaration of victory, but U.S.-backed fighters in Raqqa aren't waiting for one.

The Islamic State of Iraq and Syria (ISIS) is finished in Raqqa, they said, after hundreds of extremists surrendered over the weekend.

They've had some help from U.S. airstrikes, but the Syrian militiamen that did the fighting on the ground are the very definition of a ragtag army.

Syrian fighters dance in Raqqa. CBS News

Shiar Kakhorki showed CBS News his homemade hand grenades -- held together with Scotch tape.

Shiar Kakhorki displays a homemade grenade. CBS News

As they clear the city, ISIS gunmen still lurk in tunnels and buildings.

ISIS claimed to be men of God when they seized Raqqa over three years ago. In truth, they were bloodthirsty thugs, beheading their enemies and selling women as sex slaves.

What's left is the carcass of a city pulverized by artillery, flattened by airstrikes and deserted by its people. So many empty houses were turned into fighting positions during the battle, and destroyed in the process.

Yunus Omar and his family finally escaped Raqqa Monday, some of the last to get out. Like other civilians, they were used by the extremists as human shields.

They tried to leave twice before and were shot at by ISIS fighters, Yunus said, but Monday they didn't see any.

Yunus Omar was finally able leave Raqqa with his family. CBS News

Clearing Raqqa of explosives laid by ISIS could take months, but the city is no longer a stronghold for terrorists. The ISIS leaders who are still alive are thought to have fled south toward the border with Iraq months ago.