Barrel bombs dropped from Syrian aircrafts have killed 517 people in the northern province of Aleppo since Dec. 15, according to the Syrian Observatory for Human Rights.
The monitor said 151 of those killed by the barrels packed with explosives were children, and 46 were women.
More from GlobalPost: At least 25 killed in airstrike on Aleppo market
At least 46 opposition fighters, including 34 rebels and 12 jihadists from Iraq and the Levant were also killed, but the majority of the dead were civilians, the British-based Observatory said.
It strongly condemned the attacks and urged the international community to intervene in the situation.
"The Observatory considers all those who remain silent in the international community as complicit in the massacres that have been committed and continue to be committed by the Syrian regime," it said.
Towns and villages across Aleppo have been relentlessly targeted by aerial attacks in recent week. On Saturday, helicopters dropped TNT-packed barrels on a vegetable market next to a hospital in Aleppo city, killing 25 civilians.