At least 20 people have been killed by a car bomb outside the northern Syrian city of Manbij, the country's civil defence said.
All but one of the dead are women. They were killed when the explosive detonated next to a lorry carrying agricultural workers. Fifteen people were injured. No group immediately claimed responsibility.
A resident said the vehicle that exploded was parked by the side of the road. Recurring attacks have forced residents to become more vigilant, he added.
“There are efforts from the people of Manbij to focus on protecting some neighbourhoods, as well as setting up surveillance cameras in the main neighbourhoods of the city,” Jameel Al Sayyed, a Manbij activist and journalist told the AP.
It is the seventh car bombing to occur in Manbij, in Aleppo province, in the past four weeks, Syria's deputy director of civil defence Munir Mustafa said.
The repeated attacks raise questions about how the new government in Syria, dominated by former rebel group Hayat Tahrir Al Sham, will keep people safe. The group led the assault that last month toppled the regime of former president Bashar Al Assad.
Mr Mustafa warned that attacks in the province are a threat to the country's progress to bring about postwar security and economic recovery. Most of the explosions took place at night.
“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 ... threaten their lives, deepens their humanitarian tragedy, undermines educational and agricultural activities and livelihoods and worsens the humanitarian situation in Syria,” he said.
The Syrian presidency said it would hold to account those responsible for what it described as a "terror attack".
"This crime will not pass without the most severe punishment against its perpetrators, to serve as an example against those who will try to tamper with the security of Syria or harm its people," the presidency said.
Manbij changed hands numerous times during Syria's 13-year civil war, most recently in December when Turkish-backed groups captured it from the US-backed Syrian Democratic Forces, which is led by the Kurdish People's Protection Units militia. The SDF took Manbij from ISIS in 2016.
- Agencies contributed to this story