Aleppo is the country's largest city and has largely been home to supporters of the embattled regime.
Activists protesting President Bashar Assad's regime denied any involvement in the blasts and accused the regime of setting off the blasts to smear the opposition as government forces pummel rebels in one of their main strongholds, Homs.
The Syrian military stepped up its siege on Homs on Friday by sending soldiers in on foot. Hundreds have reportedly been killed over the past week.
Across the country, troops opened fire on anti-regime protesters who streamed out of mosques after Friday prayers nationwide. At least 27 people were killed in those attacks.
The Associated Press contributed to this report.