As many as 71 people were killed in Syrian aerial bombardment on militant-held areas in the country's northern city of Aleppo, a monitoring group said on Saturday.Syrian helicopters dropped crude barrel bombs on the al-Sha'ar neighbourhood in Aleppo, killing 12 people and injuring 15 others, said the Syrian Observatory for Human Rights.The Britain-based watchdog added that 59 more people were killed in similar bombing on al-Bab city, which is controlled by the Islamic State (IS) militants in the countryside of Aleppo. The toll could rise due to the large number of critically wounded people, Xinhua news agency reported.Aleppo, Syria's second largest city, has been carved out between the rebels and government troops. The city, once the economic capital of Syria, has suffered huge destruction.