The United States and the SDF have repeatedly called on governments to repatriate their citizens from northeast Syria, a call that has gone largely unheeded.

The UK has said it will bring back unaccompanied children but will not repatriate British adults. The UK government has stripped citizenship from several dozen IS suspects it believes have or are entitled to a second citizenship.

The SDF holds an estimated 10,000 men in prisons for IS suspects, alongside at least 750 children. In addition, over 60,000 mostly women and children are held in two detention camps, Roj and Al Hol.

Most of these detainees were captured by the SDF following the last stand of IS at Baghouz in eastern Syria in 2019.

Across the border in Iraq, 11 Iraqi soldiers were killed in their sleep in a separate overnight attack by Islamic State fighters on a military base in the eastern province of Diyala, Iraqi officials said.

Diyala governor Muthann Al-Tamimi accused the Iraqi army of being caught unprepared, according to the Iraqi News Agency. 

“The base is fortified. There is a thermal camera, night vision goggles and a concrete watch-tower,” he said. 

“The terrorists exploited the cold and the negligence of the soldiers,” he alleged, adding that the attackers then escaped to the neighbouring province of Salaheddin.

IS sleeper cells have maintained a low-level insurgency in Iraq since their military defeat in their former stronghold of Mosul in 2017. Thursday’s attack, some 75 miles north of the capital Baghdad was one of the deadliest against the Iraqi military in recent months.