Reports say the school was targeted in a terrorist attack
At least four children died when shells landed near a school in government-held western Aleppo, the Syrian Observatory for Human Rights has said.
Syrian state news agency SANA said the school in the al-Suleimaniya area had been targeted in a terrorist attack.
In the rebel-held eastern part of the city, bombing killed 145 people in the last two days, according to the head of the Civil Defence rescue service there, Ammaral Selmo.
Syrian and Russian air strikes targeting rebel-held districts of Aleppo intensified on Tuesday, after a lull of several days designed, according to the Syrian army, to allow civilians caught in the bombing to leave.
The Russian Foreign Ministry said Russia's embassy in Damascus was targeted in a mortar attack.
The embassy compound was strewn with shrapnel, but none of embassy staff were hurt, it said.
Aleppo, a northern city that was once a thriving trade hub, has become a central battleground in the five-year-Syrian war and is facing a humanitarian disaster.
The city's mayor has spoken of a "holocaust", and the United Nations has warned it could be destroyed by Christmas is the onslaught continues.
The besieged population of 275,000 - including 100,000 children - is in desperate need of food, water and medical supplies.
A US-Russia brokered ceasefire crumbled almost immediately, and the Syrian government launched an assault to capture rebel-held areas in the east of the city.
US Secretary of State John Kerry broke off talks with Russian Foreign Minister Sergei Lavrov over the offensive, which has included air strikes on hospitals.
The US and France say the offensive amounted to war crimes for which Syria and Russia were responsible.
Nevertheless, Mr Kerry will meet his Russian counterpart in Switzerland on Saturday to discuss the crisis.