The Britain-based group said it was unclear if the raids on Aleppo's Marjeh district were carried out by aircraft belonging to the Syrian government or its ally Russia.
The latest civilian deaths come as rebels press an assault intended to break a government siege of opposition-held Aleppo that began on July 17 and has raised fears of a humanitarian crisis.
The assault started on Sunday and is targeting the Ramussa district that contains the main supply route to the government-held west of the city.
After some initial advances, government forces backed by Russian air strikes have pushed back opposition fighters, which include jihadists from Al-Qaeda's former Syrian affiliate.
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According to the Observatory, at least 112 civilians, including 33 children, have been killed in Aleppo since the rebel assault began on Sunday.
The deaths include 65 people, among them 22 children, killed in rebel fire on government neighbourhoods, the Observatory said.
Another 42 people, including 11 children, have been killed in strikes on eastern Aleppo, the monitor said.
Elsewhere in Aleppo province, the monitor said an alliance of Kurdish and Arab fighters was advancing inside the Islamic State bastion of Manbij.
Observatory chief Rami Abdul Rahman said the Syrian Democratic Forces (SDF) now held 70 percent of the town.
"The Islamic State has entered its final phase in the town of Manbij," he told AFP, adding however that IS was keeping a number of civilians there as human shields.
"The progress the SDF has made in the last week is more than it was able to achieve in previous weeks put together."
Manbij sits on the route between the Turkish border and the eastern city of Raqa, the jihadists' de facto capital in Syria.