More than three years ago, the remnants of al-Qaeda in Iraq began seizing territory in western Iran and eastern Syria and restyled themselves as ISIS, a new “caliphate” of radical Islamist terror. Today, their last claim on any significant territory came to an end in their self-proclaimed capital. US-backed forces, primary the Syrian Kurd YPG, took complete control of Raqqa earlier today, although mop-up work will continue for some time:

U.S.-backed militias raised a flag inside Raqqa stadium on Tuesday, a Reuters witness said, as a four-month battle to take Islamic State’s Syrian capital came to an end.

The fighting was over but the alliance of Kurdish and Arab militias was clearing the stadium of mines and any remaining hiding militants, said Rojda Felat, commander of the Raqqa campaign for the Syrian Democratic Forces (SDF).

A war monitor, the Syrian Observatory for Human Rights, said Islamic State was now completely cleared from the city.

The fall of Raqqa city, where Islamic State staged euphoric parades after its string of lightning victories in 2014, is a potent symbol of the jihadist movement’s collapsing fortunes. From the city, the group planned attacks abroad.

The command and control structures of ISIS have been destroyed in Raqqa, but not all of the fighters have been eliminated. One pocket of resistance remains, a stadium complex which the terrorists turned into a torture dungeon for political prisoners. Dozens of fighters may still be trapped there, although no one’s quite sure yet:

Earlier Tuesday, the Kurdish-led SDF forces captured the city hospital, the other last remaining IS holdout in Raqqa. The facility had doubled as a hospital and an IS command center.

Its capture left IS militants cornered in and around the notorious stadium, which they had turned into a huge prison where they incarcerated anyone who opposed their brutal rule. After Sillo’s statement, it was not immediately clear if the IS militants were still inside the stadium.

Also earlier, Musafa Bali, a spokesman for the SDF, said 22 IS militants were killed in the advance on the hospital.

“The stadium is a huge structure with underground rooms and tunnels. There are also buildings around it” still under the control of IS, he said and added that “there is nothing decisive today.”

Observers in the city claim that a significant number of fighters bugged out of Raqqa before the final collapse of IS, destinations unknown. CNN also reports that the airstrikes have stopped after months of bombardment:

There was only one US airstrike in Syria Monday, but that was far from Raqqa, where there haven’t been any for two days, a further indication that the battle for the city is almost over. Dillon said the SDF hadn’t asked for any more air support, meaning the coalition was confident that there were no more ISIS fighters left.

“Raqqa is being Slaughtered Silently,” the award-winning network of citizen journalists who remained in the city throughout the occupation, tweeted Monday that 30 buses and 10 trucks were used to transfer ISIS fighters from Raqqa.

The group did not say where the fighters were taken.

Just as has been the case in western Iraq, not all fighters fled or fought to the death. A number of them surrendered — once unthinkable for ISIS terrorists — and some have even taken up the forbidden practice of smoking:

Those buses and trucks most likely made one-way trips and not repeated evacuations. Just getting out of a besieged city once would be tricky, let alone re-entering it and trying again. If that’s the case, then perhaps as many as 300-350 fighters got out of Raqqa. That’s not much of an army, but it’s still a significant terrorist network.

One has to wonder just how high morale will be, though, after the humiliation of losing the “caliphate” capital of Raqqa, their largest city in Mosul, and Dabiq, the city of prophecy for divine grant of a caliphate. The question of whether Abu Bakr al-Baghdadi is an anointed prophet or just a homicidal lunatic has to be at least scratching the borders of their consciousness by now. The next order of business might be a leadership fight that could finish off most of the rest of the homicidal lunatics … or so we can hope.

CBS’ Holly Williams reports from the scene of Raqqa about what comes next. Watch the film to see just how much of the city is left to hold. “It is a terrible irony,” Williams says, “that in order to retake Raqqa from ISIS, they had to destroy it.” That’s precisely why we should have remained on the ground to ensure that al-Qaeda in Iraq stayed defeated six years ago.

Update: The original headline read “US forces,” but I meant to write “US-backed forces.” I’ve corrected it above.