After nearly a week of fighting and US-led coalition airstrikes, the siege — believed to be the biggest coordinated attack by ISIS since the fall of its so-called caliphate nearly three years ago — finally came to an end.
The attack on the prison has stoked fears the terror group, which has flown largely under the radar since losing its territory in Iraq and Syria, could be making a resurgence.
The SDF’s media commander, Siyamend Ali, told CNN that the attack had been coordinated and planned over the course of six months. “This operation is one of the largest targeted operations that Da’esh (ISIS) executed,” Ali said. “According to the detainees who we interrogated at the first moments of the operation, the operation was prepared and planned for six months.”
More than 100 ISIS fighters launched the assault on Ghweran prison in Hasakah on Thursday, detonating three car bombs before storming into the complex in an attempt to break out thousands of their comrades, many of whom were detained after the group’s 2019 defeat.
The SDF, which oversee Ghweran prison, said the ISIS fighters struck local forces standing guard outside, while the militants inside burned blankets and plastic items “in an attempt to create chaos.” The Kurdish-led forces, a key US partner in the fight against ISIS, said they “thwarted” the attempted jailbreak hours after it began.
However, clashes were still ongoing near the facility until Wednesday, when the group’s spokesman, Farhad Shami, said that all ISIS fighters and prisoners had surrendered.
There was “mass surrendering of ISIS prisoners,” Shami added.
He also shared videos on Twitter which appeared to show hundreds of prisoners in orange jumpsuits gathered in a courtyard, with the walls behind them blackened from the fighting.
The Pentagon said on Tuesday that the US-led coalition had moved in armored Bradley fighting vehicles to support the SDF, indicating that US ground forces were involved in the fight. The Bradleys were being used to help establish an inner and an outer perimeter around the prison facility, while the SDF closed in on ISIS fighters, according to US military officials.
“We have provided limited ground support, strategically positioned to assist security in the area,” John Kirby, the Pentagon spokesman, told reporters in Washington.
Coalition forces also supported the operation with airstrikes, including the precision targeting of ISIS fighters who were attacking SDF positions from the cover of nearby buildings.
No US service members were injured during the fighting, a defense official said, although the SDF suffered some losses. Dozens of fighters with the SDF and ISIS are estimated to have been killed in the fighting.
Operation Inherent Resolve (OIR), the US-led coalition mission to defeat ISIS, said in a statement Tuesday that the recent ISIS escape attempt “will not pose a significant threat to Iraq or the region.” It added that assessments are ongoing to see if ISIS is planning any future attacks on Ghweran or other prison facilities throughout Syria or Iraq.
“Due to its severely degraded capability, Daesh’s future survival is dependent on its ability to refill its ranks through poorly-conceived attempts like the Hasakah attack,” said Maj. Gen. John W. Brennan, Jr., the commander of the OIR Combined Joint Task Force.
Some 11,000 to 12,000 ISIS fighters are held in northern Syria in prisons and detention camps run by the SDF.
Although there is little fear that ISIS will reclaim its former physical territory, which, at its peak, stretched from the outskirts of Baghdad to western Syria and encompassed more than 10 million people, the terror group has been mobilizing thousands of its remaining fighters in recent years.
In recent months, Iraqi security forces and commanders have also warned that ISIS sleeper cells are continuing to stage attacks.
Following a deadly ambush on an Iraqi military post near Baghdad last Friday, Iraqi President Barham Salih tweeted: “Certainly, the attempts to revive terrorism in the region cannot be underestimated.”
CNN’s Oren Liebermann, Ellie Kaufman, Mohammed Tawfeeq and Joshua Berlinger contributed to this report.