At least 29 militants were killed in battles with the Syrian government forces near a key route in Syria's Aleppo city, a Human Rights monitor group reported on Sunday.The Al-Qaeda-linked Nusra Front militants were killed during a failed overnight attempt to re-open their last remaining supply route, Castello road, that connects rebel-held areas in the northern countryside of Aleppo with rebel-controlled areas in the eastern part of the city, Xinhua news agency quoted the Syrian Observatory for Human Rights as saying.The Syrian army had severed the road on Thursday, following a week-long offensive. Aleppo, strategically located near the borders with Turkey, is Syria's largest city and once an economic hub. It has been a focal point of clashes between the Syrian army and the rebels.