Activists said Tuesday that more than 70 prisoners took advantage of infighting between rival rebel groups to escape from an Islamic State of Iraq and Syria (ISIS) jail in Syria.
The Britain-based Syrian Observatory for Human Rights and activist Bari Abdelatif, who is from the town where the escape occurred but has fled to Turkey, said Kurdish fighters captured by ISIS in recent months were amongst the escapees on Monday.
The militants went house-to-house and set up checkpoints around the northern town of Al-Bab, searching for those who fled.
The prisoners took the opportunity to escape when clashes erupted between rival militant groups, said Bari Abdelatif, an activist from al-Bab who is now based in Turkey.
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"There are checkpoints everywhere," Abdelatif said of the situation in the town. He said he was in contact with residents and added that ISIS fighters were driving through town streets and calling on people over loudspeakers to hand over any prisoners they were hiding.
The Observatory said the extremists were able to recapture some of those who fled but did not provide details or numbers.
Al-Bab sits less than 30 miles south of Syria's border with Turkey, and has thus become a gateway for militants crossing the border -- in both directions. The jail break on Tuesday came on the heels of reports that a group of ISIS defectors being held at a separate jail in the area had attempted to escape and run for the border over the weekend.
According to accounts online, that attempt ended with about five of the defectors being shot and the rest being recaptured.
ISIS captured about a third of Syria and a third of neighboring Iraq last year. In the past months, the group has been defeated in some areas, including the Syrian border town of Kobani and several surrounding villages.
Across the border in Iraq, ISIS was being fought on several fronts by a rag-tag alliance of government forces, Kurdish fighters, Iranian-backed Shiite militias, and Sunni tribesmen.
An Iraqi official said Tuesday that state-allied forces had managed to wrest control of another small town on the outskirts of Tikrit. ISIS has held Saddam Hussein's hometown since the summer, but is being increasingly encircled by the Iraqi forces.
Meanwhile, as CBS News correspondent Holly Williams reported Tuesday, Kurdish fighters battling ISIS in nearby Kirkuk province said they were clawing back significant territory from the extremists with the help of U.S.-led airstrikes.
The U.S. military is not playing any role in the fight for Tikrit, which is being viewed as a major test of the Iraqi government forces and their allies on the ground ahead of the larger anticipated battle for Mosul, Iraq's second largest city, which ISIS also captured in the summer.