At least eleven people were killed and several others wounded in a mortar attack by foreign-backed militants in Syria's Northern city of Aleppo. "Eleven killed and 20 others injured in a terrorist mortar attack on Jamilia district," the official news agency SANA cited a police source in the city as saying on Monday. The so-called Syrian Observatory for Human Rights also confirmed the attack, saying the foreign-backed Takfiri militants were behind the incident. The London-based group added that the victims were civilians, including three children. On Sunday, Syrian government forces attacked the militants near al-Naqarin, in the suburbs of Aleppo. The troops captured a warehouse used by the militants in Tal al-Zarzour neighborhood and killed all the insurgents there. Army units also confiscated all weaponry and missiles stored in the warehouse. This is the latest in a series of army advances in the area. Last week, army units secured the al-Dweireneh town, situated in East of the al-Nayrab airport in Aleppo. Syria has been gripped by deadly unrest since 2011. According to reports, the western powers and their regional allies -- especially Qatar, Saudi Arabia, and Turkey -- are supporting the militants operating inside Syria. In a recent statement, the United Nations High Commissioner for Refugees said the number of Syrian refugees, who have fled the country’s 29-month-long conflict, reached two million. The UN refugee agency also said some 4.2 million people have also been displaced inside Syria since the beginning of the conflict in the Arab country.