Islamic State group jihadists demolished a notorious government prison in the historic Syrian city of Palmyra on Saturday, as barrel bombs dropped by government helicopters killed more than 70 civilians in Aleppo.

In neighboring Iraq, government forces retook an area west of Ramadi, which IS overran earlier in May.

Observers said IS planted explosives that "largely destroyed" the Palmyra jail, which was for decades a symbol of abuses meted out on government opponents.