At least 20 people, most of them women, have been killed in a car bomb attack in northern Syria, the country's presidency says.

Hospitals workers say at least 19 people were killed all but one of them women when a car bomb exploded on the outskirts of a northern Syrian city.

A car bomb killed at least 15 people in the northern Syrian city of Manbij on Monday, the second attack there in three days and Syria's deadliest since Bashar al-Assad was toppled from power in December.