Syrian Army retook today most of Aleppo's prison, in fighting that has killed at least 46 people over two days.
But the fate of hundreds of prisoners reportedly freed after Islamist and jihadist fighters overran the facility was unclear, with suggestions that they may not have been able to flee amid the fighting.
Clashes in part of the jail and on its perimeter resumed between Syria Army and militants of Ahrar Al-Sham Brigade and Al-Qaeda affiliate Al-Nusra front, the Britain-based watchdog said.
Observatory director "Rami Abdel Rahman" told AFP Thursday that the militants assault began with a suicide attack by an Al-Nusra fighter at the prison's main entrance, opening the way to an assault on the facility.
He said the fighters had taken control of 80 percent of the jail and freed hundreds of prisoners.
Ahrar al-Sham said opposition fighters had taken full control of the prison, as did the Aleppo Media Centre, a citizen-journalist outlet. But Syrian television said soldiers and security forces had thwarted the attack.
For months, militants have launched attacks on the prison, which reportedly holds some 3,000 detainees, including Islamists, activists and minors. But they have always failed to seize full control.
Conditions inside are said to be dire, with the Observatory reporting outbreaks of tuberculosis and other diseases. The conditions prompted the government to announce in December the release of 366 prisoners for "humanitarian reasons".