Syrian troops on Friday retook most of Aleppo's prison, after losses a day earlier, in fighting that killed at least 47 people in two days, a monitoring group said.
But it was unclear if hundreds of prisoners had been able to flee, as reported on Thursday after Islamist and jihadist fighters had overrun the facility.
The Syrian Observatory for Human Rights said regime aircraft were keeping up their daily assault on rebel-held districts of the northern city with barrel bombs.
The crude weaponry has killed at least 260 people since Saturday, including 73 children, according to the monitoring group.
It said that 12 other people, including three children, were killed on Friday in mortar attacks targeting regime-held areas of Aleppo city.
Fresh clashes in and around part of the jail broke out between government forces and fighters of Ahrar Al-Sham Brigade and Al-Qaeda affiliate Al-Nusra front, the Britain-based watchdog said.
The 47 dead over two days were 20 soldiers, 22 rebels and five prisoners, it said.
Observatory director Rami Abdel Rahman told AFP the rebel assault began with a suicide attack by an Al-Nusra fighter at the prison's main entrance.
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Ahrar al-Sham said Thursday that opposition fighters had taken full control of the prison, as did the Aleppo Media Centre, a citizen-journalist outlet.
But state television said soldiers and security forces had thwarted the attack.
Rebels have for months launched attacks on the prison, which reportedly holds some 3,000 detainees, including Islamists, activists and minors.
Conditions inside are said to be dire, with the Observatory reporting the death of some 600 prisoners because of extreme medical and food shortages, as well as violence around the prison in recent months.
The conditions prompted the government to announce in December the release of 366 prisoners for "humanitarian reasons".
In addition to Aleppo, the Observatory said army helicopters on Friday also dropped barrel bombs in parts of Idlib, Hama, Daraa and Damascus provinces.
In Hama's Kafr Zita, 11 people including five children were killed in the latest such attacks, whose use has been widely condemned by rights groups as indiscriminate.
Syria's nearly three-year-old conflict is estimated to have killed more than 136,000 people.