Al-Jazeera Video: Syria rebels fend off Aleppo assault

"Syrian rebels held off an offensive by regime forces in Aleppo Saturday as the head of the main opposition bloc called for heavy weapons and said President Bashar al-Assad should be tried for "massacres".

After massing for two days, troops backed by tanks and helicopter gunships moved on southwestern Aleppo where rebels concentrated their forces when they seized much of the northern city on July 20.

Al Jazeera's Jamal al-Shayyal reports."