Turkish troops and allied Syrian rebels expelled ISIS from the last strip of territory it controlled along the Syrian-Turkish border on Sunday, effectively sealing the extremists' self-styled caliphate off from the outside world, Turkey's state-run news agency reported. Also on Sunday, Syrian pro-government forces backed by airstrikes launched a wide offensive in the northern city of Aleppo, capturing areas they lost last month and besieging rebel-held neighborhoods, state media and opposition activists said, per the AP. Turkey-backed Free Syrian Army rebels have cleared the area between the northern Syrian border towns of Azaz and Jarablus, the Anadolu news agency reported. It said the advance "has removed terror organization (ISIS)'s physical contact with the Turkish border in northern Syria." The FSA's advance shut down key supply lines used by ISIS to bring in foreign fighters, weapons, and ammunition.
Meanwhile, the recapture and return to siege of rebel-held parts of Aleppo dealt a major blow to insurgent groups. They have lost scores of fighters in recent weeks in the battle to open a corridor into the city and lift the government's blockade. After the government laid siege on Aleppo in July, the United Nations said that nearly 300,000 residents were trapped in rebel-held neighborhoods, making it the largest besieged area in war-torn Syria. State TV quoted an unnamed military official as saying that troops are now in full control of the military academies south of Aleppo and are "chasing the remnant of terrorists." It added that all roads linking rebel-held eastern Aleppo with opposition areas outside the city "have been cut." Turkey has launched two incursions into Syria since Aug. 24 in an operation designed to drive ISIS away from the border and prevent the advance of US-backed Kurdish forces, which are also battling the extremist group.