The UK-based Syrian Observatory for Human Rights also reported the attack, saying that medical sources accused regime warplanes of pounding the Sukkari neighborhood with barrel bombs "laden with poison gas."
Harrowing footage distributed by the Syrian Civil Defense -- also known as the White Helmets -- shows small children and other victims being rushed to the makeshift Basel Aslan hospital in the arms of rescuers, gasping desperately for air as they are given oxygen masks.
The video also shows a boy being washed with a hose by rescuers after being pulled from the rubble as the sirens of ambulances wail around him.
Another video by the Aleppo Media Center shows a man laying almost lifeless at the same hospital as medics try to pump oxygen into his lungs.
Such scenes are becoming all too familiar in Aleppo, part of which has been held by rebels since July 2015. Government forces in July encircled the rebel-held part of the city in a siege that cut residents off from basic supplies of food, water, fuel and medicine, spawning a humanitarian crisis.
Rebel-held Aleppo has been pounded by the forces of President Bashar al-Assad's regime, backed by Russian air power. Several cases of chlorine gas bomb attacks also have been reported there.
A UN investigation in late August found that chemical weapons had been used in Syria
, both by the national air force and ISIS militants. It found two instances where regime forces had used chlorine as a chemical weapon, and one where ISIS had used mustard gas.
In late August, a helicopter dropped two barrel bombs on a funeral wake for children
in Aleppo, killing at least 16 people, Syrian monitoring groups said.
Elsewhere in Aleppo province, ISIS attacked a Turkish military position on Tuesday, killing two soldiers and wounding five others, the Turkish military said in a statement. Another attack killed two Free Syrian Army fighters and injured two others, the military said.
ISIS said its forces destroyed two Turkish tanks with guided missiles in the northern suburbs of Aleppo province, killing a number of Turkish soldiers. It said that a suicide bomber carried out the second attack among FSA soldiers.