Meanwhile, the Syrian information minister says President Bashar al-Assad will lead any transitional government if one is agreed at peace talks due to take place in January in Geneva.
Opposition groups have demanded that Mr Assad step down.
The Syrian Observatory for Human Rights (SOHR), a UK-based activist group with links to the opposition, said 18 people had been killed in the Aleppo attack, including 10 government soldiers.
The attack on the Furqan and Meridian neighbourhoods also wounded at least 30 people, the SOHR said.
More than two million Syrians have fled the country, according to the UN. Since the start of unrest in March 2011, more than 100,000 people are estimated to have been killed in the conflict.
In the early months of the uprising Aleppo, Syria's commercial capital, was largely spared the violence.
But the course of the conflict dramatically shifted in summer 2012, and the northern city became an battleground.
Peace talks are scheduled to take place in Geneva on 22 January, the UN says.
Syrian Information Minister Omran al-Zoubi said any transitional government agreed at the talks would be led by Mr Assad.
He said the American so-called Arab Spring project in the region had failed.
