BEIRUT: The increasingly embattled Islamic State (IS) hit back against the army assaults they have faced in recent times, launching twin suicide attacks in Aleppo which killed 15 people.IS claimed responsibility for the attacks, with one attacker detonating a car bomb near the IS-held town of Deir Hafer, killing eight fighters of regime forces late on Saturday, the Syrian Observatory for Human Rights monitoring group said. The militant organisation said the attack “was carried out by fighter Abu Abdullah al-Shami with an explosive-laden vehicle”.Deir Hafer lies on a key road linking Aleppo city to the IS-controlled town of Khafsah, which holds the main station to pump water into Aleppo, and further east to the jihadist group’s de facto capital Raqqa. Residents of Aleppo city have been without main station water for 48 days after the jihadists cut the supply.On Sunday, Russian and regime war planes bombarded IS positions in support of Syrian troops, which had advanced to nine kilometres from Khafsah, the Observatory said. They were just six kilometres from the pumping station, Observatory Head Rami Abdel Rahman said.The second attack occurred in the rebel-held town of Azaz, in which IS said a fighter “detonated his suicide belt”. The Observatory said the suicide attack in the town “killed seven fighters and wounded several others, some of them in critical condition”.The United Nations on Sunday said 26,000 people had fled the fighting since late February, while the Observatory said as many as 30,000 had been displaced.