A double bomb attack in Aleppo carried out by Al-Qaeda-affiliated group, the Islamic State of Iraq and Levant (ISIL), claimed the lives of at least 16 Syrian rebel fighters on Sunday, an NGO said. An ISIL fighter blew himself up at the headquarters of an Islamist rebel brigade in the Aleppo town, while a car bomb detonated outside at the same time, the Syrian Human Rights Observatory said, Al-Arabiya reported. The bomber had reportedly offered to negotiate with the rebels in the name of ISIL, but detonated an explosive belt inside the headquarters. The attack, which took place in the town of al-Ra'ei, not far from the Syrian border with Turkey, also injured another 20 rebel fighters, the Observatory said. The report added that the bombings came as fighters gathered at the headquarters to discuss the possibility of a truce in the fighting with ISIL that has raged throughout rebel-controlled areas. The rebel-jihadist clashes have killed around 1,400 people since they began, although the Observatory says the real toll is likely much higher because both sides are secretive about their losses. Meanwhile, the ISIL has formed two female battalions in Syria’s Northern city of Raqqah, pan-Arab newspaper Asharq al-Awsat reported on Sunday. The battalions were reportedly launched as part of ISIL’ efforts to “expose male activists who disguise in women’s clothing to avoid detention when stopping at the ISIL checkpoints”.