Castello Road is one of the exits that should be used for evacuation of civilians and militants who want to leave eastern Aleppo controlled by terrorists.
Small arms and heavy machine guns fire has been heard. The Syrian soldiers responded with machine guns' fire, the correspondent reported.
The attack began several minutes before the humanitarian pause ended.
A humanitarian pause in Russian and Syrian airstrikes on terrorist positions came into force in Aleppo earlier today. It will last until 7:00 p.m. local time (16:00 GMT). Civilians are encouraged to leave the war zone through six corridors, while two others are reserved for militants willing to lay down their arms.
Earlier in the day, a militia source told RIA Novosti that al-Nusra Front militants opened fire at civilians who wanted to leave Aleppo via the Bustan al-Qasr humanitarian corridor.