MOSUL -- Iraqi forces opened exit routes this weekend for hundreds of civilians to escape Mosul. Iraqi forces backed by the U.S. military are making a final push to drive ISIS out of a city now in ruins.

U.S.-backed Iraqi special forces said Sunday they've retaken two-thirds of the Old City, but it's come at a cost.

Commanders finally decided that the suffering of tens of thousands of civilians still trapped inside this brutal battle outweighed of any hope of leaving the Old City intact -- especially after ISIS robbed Iraqi forces of a symbolic victory by blowing up the al-Nuri mosque, where ISIS leader Abu Bakr al-Baghdadi declared the creation of the so-called caliphate more than three years ago.

Iraqi special forces said on June 25th that they have driven out two-thirds of ISIS fighters from Mosul. CBS News

CBS News entered the Old City with Iraqi special forces, the very forces that broke through ISIS defenses and started advancing toward the mosque.

CBS News and the special forces drove until the streets got so narrow we had leave the protection our humvees behind and get out on foot as gunfire and mortars rang out in every direction.

The scene in Mosul on June 25, 2017. CBS News

The stench of death from the bodies of ISIS fighters rotting in the sweltering heat filled the air.

As you walk around the streets of the Old City, you just get an indication of the damage and destruction. Whole neighborhoods have ceased to exist after eight months of fighting - and it's not over yet.

General Abdul Ghani al-Assadi said they're starting to face female ISIS fighters on the battlefield for the first time.

"It's their ultimate point of weakness now," he said. "But they're also the women of ISIS, so they have the same ideology, that's why they're fighting."



Iraqi special forces have opened up roads for civilians to escape in Mosul. CBS News

The Iraqi military has begun opening exit routes for shell-shocked residents to flee the Old City, with the U.N. warning of a rising civilian death toll and the "unimaginable" risks facing those trapped inside.

As the battle enters its final phase, Iraqi soldiers are not locked in a fight against ISIS holdouts -- but a fight against time.