US-backed Kurdish-led forces say they have wrestled back control of the last section of a prison controlled by Islamic State militants, ending a week-long assault by the extremists on one of the largest detention facilities in Syria.
It's understood an Australian teenager caught in the crossfire is alive and in the custody of Kurdish forces, but there are concerns that he needs medical attention.
The attack was the biggest by IS militants since the fall of the group's "caliphate" in 2019.
In the week of clashes, dozens from both sides were killed, the US-led coalition carried out nearly a dozen air strikes and thousands of civilians living nearby were displaced.
"The whole prison is now under control," said Farhad Shami, a spokesman for the US-backed Syrian Democratic Forces (SDF), early on Thursday AEDT.
"The operation today was on the cells where child detainees were held.
"We were able to surround a number of terrorists who had taken [other prisoners] as shields and we killed [the terrorists]."
Mr Shami said the force was then able to enter the cells and the remaining militants surrendered. A large number of children were freed, he said, but he had no specific number.
He said about 3,000 inmates had surrendered.
The militants' use of child detainees as human shields had slowed down the effort to retake the facility, located in the north-eastern city of Hasakah, Kurdish officials said.
Australian teenager in custody
Earlier this week the ABC reported an Australian 17-year-old who had spent the past three years in the Guweiran, or al-Sinaa, prison had sent a handful of short voice recordings describing the situation inside to his family in Sydney.
The ABC understands the teen survived the outbreak of violence after the Kurdish forces successfully regained control of the prison.
The boy, who the ABC cannot identify, said in the recordings that he suffered a head wound as gunfire and explosions rattled around him.
It's understood he has been in Syria since 2015, when he travelled to the newly declared Islamic State caliphate with his parents and siblings.
At least 40 Australian children remain in detention of some form across the north-east of Syria, according to the organisation Save the Children.
Foreign Minister Marise Payne told the ABC earlier this week she was seeking advice about the matter.
Prison staff held hostage
After breaking into the prison late on January 20, the IS militants were joined by others rioting inside the facility.
Around 200 armed militants were believed to be holed up in the northern wing at one end of the prison complex, holding hostages from among the prison staff.
The complex houses more than 3,000 inmates, including around 600 minors. Children have reportedly been killed and wounded in clashes, rights and aid groups say.
According to the UK-based Syrian Observatory for Human Rights, 124 IS militants, 50 fighters with the Kurdish-led forces and seven civilians died in the week-long attack that extended outside the walls of the prison into residential areas.
The Syrian Democratic Forces said that, earlier on Wednesday it had freed 23 of its servicemen held hostage by IS militants. Later it said inmates continued to surrender.
Backed by US-led coalition armoured vehicles and air support, the SDF had been closing in on the prison wing controlled by the armed militants.
Fighters from the SDF and other security teams took control of adjacent buildings and used loudspeakers to call on the militants to surrender.
Total number of escapees unclear
The Islamic State group's territorial control in Iraq and Syria was crushed by a years-long, US-backed campaign, but some fighters remained at large in sleeper cells that, increasingly, have killed scores of Iraqis and Syrians in recent months.
Prison riots have been common, where thousands of suspected IS militants have been held. But the attack launched last week was the boldest and most ambitious.
Sleeper cells from outside the prison, numbering nearly 100 fighters, attacked the facility after dark, ramming vehicles against its walls and detonating car bombs to create a diversion.
They were joined by rioting inmates, and some managed to escape.
The SDF said the total number of fugitives remained unclear.
ABC/wires