Russian and Syrian air raids on the rebel-held eastern half of the city of Aleppo have forced the closure of the largest hospital in the area and killed two people. <br/><br/>The Syrian American Medical Society, which supports the hospital, said it had been struck by barrel bombs. <br/> <br/>There are also reports of Russian-backed Syrian government forces hitting Aleppo's historic Old City. Clashes between government troops and rebels are occurring in several areas. <br/><br/>Russian and Syrian air forces resumed attacks on the rebel-held east of the city after a partial truce lapsed on 19 September. Government forces have also launched a ground offensive against the rebels.<br/><br/>The mounting civilian death toll has sparked international protests. The US says Russia is driving moderate rebels into the arms of jihadists. <br/><br/>Once Syria's commercial and industrial hub, Aleppo has been divided roughly in two since 2012.<br/><br/>The UN says at least 400 civilians, including many children, have been killed in the city this week as a result of Russian and Syrian government attacks.