The Britain-based Syrian Observatory for Human Rights says the men were shot dead and came from the besieged Shiite-majority towns of Nubul and Zahra in Aleppo province.
Syria's conflict has taken on an increasingly sectarian tone over the last year, pitting predominantly Sunni Muslim rebels against members of Assad's Alawite sect, an offshoot of Shiite Islam.
An amateur video posted online showed two blindfolded men sitting in front of a masked gunman before they were shot.
The videos appeared genuine and corresponded to other AP reporting on the events depicted.
Unrest in Syria began in March 2011 and later exploded into a civil war. More than 100,000 people have been killed in the conflict.
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