The opposition Aleppo News Network said in a statement that the Thursday raid targeted an army base that militants had captured, killing commander Youssef al-Abbas of the Qatari-backed al-Tawhid Brigades, one of the biggest armed opposition groups. Abbas was known by the nom de guerre Abu al-Tayyeb.
Tawhid's leadership was holding a meeting in the base when the raid occurred, the statement said.
It said Tawhid's head, Abdelqader Saleh, was injured and taken to a hospital in Turkey, 45 kms (28 miles) to the north, along with Abdelaziz al-Salameh, another top commander. Both were in good condition, the statement said.
Aleppo, Syria's commercial hub and most populous city before the start of foreign-hatched unrest in 2011, has been witnessing heavy fighting since Syrian forces launched an offensive two weeks ago to retake militant-held areas in the city.
Video footage taken by activists showed the body of Abu al-Tayyeb after being transported to his hometown of Mareh in the countryside north of Aleppo.
Al-Tawhid issued a statement earlier this week, along with other terrorist groups that includ al-Qaeda-linked al-Nusra Front declaring an emergency and summoning all militants to head to the fronts.
Syria has been gripped by foreign-hatched deadly unrest since March 2011. A very large number of the militants operating inside Syria are reportedly foreign nationals.
According to reports, the Western powers and their regional allies, especially Qatar, Saudi Arabia, and Turkey, are supporting the militants operating inside Syria and are providing them with required military equipment.
NTJ/BA