MOSUL, Iraq -- Iraqi troops backed by the U.S. military are tightening the noose around the Islamic State of Iraq and Syria (ISIS) in the city of Mosul.

ISIS fighters snipe at Iraqi forces who are pushing into Mosul’s Old City, which is one of the extremists’ last strongholds.

CBS News was with Brigadier General Abbas Al Jbouri 350 yards from the frontline as he called in helicopter gunships targeting an ISIS position where they were burning tires to try to hide their location.

“This is the plan: We are going to move forward, we are going to fight ISIS house to house to liberate the civilians, but we put a safe sector for the civilian if they want to come to us,’” the general said.

The Iraqi troops are in a victorious mood on the frontline and it’s easy to understand why.

Nearly three years ago, ISIS fighters swept triumphantly across northern Iraq as many Iraqi soldiers ran away, rather than putting up a fight.

ISIS captured Mosul with ease -- a gang of violent fanatics who claimed to have established a new “Islamic State.”

Now, Iraqi forces have regrouped and ISIS has been beaten back. Some Iraqi commanders say they’ll retake the entire city within weeks.

Iraqi forces have regrouped and ISIS has been beaten back. CBS Evening News

They already have ISIS surrounded in Mosul and they’re pummeling the extremists.

But the cost of liberation is high as one city is smashed beyond recognition; Its people frightened and exhausted. They survived more than two years under ISIS only to see their neighborhoods turned into battlefields.

“God bless you,” said one woman to the troops during this horrible week.

Six days ago, the fighting was on a street where the troops defused a roadside bomb -- a parting gift from the extremists.

Mosul will soon be free of ISIS, but they’ve left the city -- and its people -- with deep scars.