BEIRUT (AP) — Syrian military helicopters dropped barrel bombs on a rebel-held neighborhood in the northern city of Aleppo on Monday, cleaving the fronts of apartment buildings and killing at least 24 people, activists said.

Government aircraft have pounded districts under opposition control in the divided city for months with the makeshift bombs— huge canisters packed with explosives and shrapnel that cause massive damage on impact. Activists say around 2,000 have been killed in such attacks in Aleppo this year alone.