The Free Syrian Army released 300 inmates from Idlib’s Central prison on Saturday after besieging the area and destroying several buildings with some regime forces were captured while others fled the scene.
According to the Syrian Observatory for Human Rights, At least 10 fighters have been killed since Friday in clashes inside the prison.
Videos posted online by activists showed rebels inside the facility at the western entrance of the provincial capital. Idlib remains under regime control, but its province is mostly opposition-held.
Dozens of prisoners were shown escaping to an outdoor area of the prison, protected by rebels, as gunfire and explosions are heard.
One man collapsed, bleeding profusely, and others were seen struggling to carry him.
Other green night-vision footage apparently from inside the prison showed bombed-out cells and dead inmates on the floor, who prisoners say were summarily executed by soldiers.
Observatory said it has documented hundreds of cases nationwide in which detainees have been tortured to death and many others permanently disabled by torture.
Elsewhere in Syria, eight rebels and one civilian were killed during clashes with troops in the central city of Homs and shelling on the nearby opposition stronghold of Qusayr, the Observatory said.
It also reported that a child died from wounds sustained on Friday in air raids on Homs, whose position on the route linking Damascus to the sea makes it a strategic point in the conflict.
Regime warplanes meanwhile raided rebel positions in the Eastern Ghouta region bordering Damascus, as troops shelled Moadamiyet al-Sham and Daraya, located southwest of the capital and near the important Mazzeh military airbase.
In Damascus, one rebel was killed in clashes with troops in the western Tishreen neighbourhood, several mortar rounds landed in the northeast district of Barzeh and a man was wounded by a car bomb in the southern district of Zahira, the Observatory said.
State television said the army had taken several positions in embattled Daraya, where troops have been massing for more than a month in a bid to oust the rebels.
Elsewhere, the Observatory reported air raids in Daraa province in the south and shelling and clashes in Aleppo province in the north.