A car explosion in northern Syria on Monday has killed at least 20 people, the Syrian presidency said, vowing to hold those responsible "for this criminal act" to account.

The blast took place on a main road on the outskirts of Syria's northern city Manbij, the civil defense said. Fourteen women and one man were killed, and fifteen other women were injured.

The Syrian Observatory for Human Rights (SOHR) put the death toll at 18 civilians, including 14 women.

Since the lightning rebellion which toppled the rule of Bashar Assad in December, Manbij has been the scene of fighting between the Kurdish Syrian Democratic Forces (SDF) and Turkish-backed fighters.

Spate of car bomb attacks in Manbij

Most of those killed were women farm workers who were being transported in a vehicle next to the exploding car, state news agency SANA reported, citing the civil defense, also known as the White Helmets. It added that the death toll was likely to climb.

There was no immediate claim of responsibility for the attack. 

The explosion is the second in three days. On Saturday, four civilians were killed and nine more were injured in another car bomb attack in Manbij.

Munir Mustafa, the deputy director of the White Helmets, said Monday's car bomb explosion was the seventh in Manbij in just over a month. 

"The continued attacks on Syrian civilian areas and targeting civilians while they are trying to recover from the effects of the war of the defunct Assad regime that lasted for about 14 years threatens their lives, deepens their humanitarian tragedy, undermines educational and agricultural activities and livelihoods, and worsens the humanitarian situation in Syria," Mustafa said.

The city lies in the Aleppo countryside, some 30 kilometers (19 miles) south of the Turkish border, with the Euphrates River to the east.

Edited by: Roshni Majumdar