Transcript for US-backed forces officially declare victory in Raqqa

more responsibility for what he heard. U.S. Backed forces officially declaring victory in raqqah. The Syrian city ISIS claimed as its capital. After months of fierce fighting on the ground the city is left vacant and in ruins. ABC's reporter back in the region tonight with a reality check. How many ISIS fighters are still there. Reporter: Tonight, raqqah liberated, the city that was the beating black heart of ISIS, finally free, and at the centre of this city, a traffic circle where the extremists beheaded their enemies, where women were sold into slavery, today the centre of victory celebrations for the u.s.-backed forces. Amongst the photos of those honored today -- we met this young female commander last July, she drove us to the front lines, saying she was fighting to protect her people from ISIS. She paid the ultimate price, killed by the militants that night. Today the city she fought for, and died in lies in ruins. Here, the soccer stadium, a gruesome reminder of the brutality that defined ISIS. Below the bleachers, a gym turned into a prison and torture chamber where enemies were stretched over gym equipment, hung from the rafters. For now ISIS is gone, only the ghosts of their many victims remain. Ian panel from Iraq tonight. You covered the movements of ISIS for years now. This victory in raqqah and the previous victory in mosul have been major advances. On the ground there are thousands of ISIS fighters in these two countries alone? Reporter: You're so right. Countless victories and the U.S. Military estimate 6,000 militants out there in Syria and here in Iraq. Helping in the battle are 6,000 military personnel who know they have had many victories but the war against ISIS is yet to be won. Much more ahead. Severe weather at this hour for

This transcript has been automatically generated and may not be 100% accurate.