A car bomb has killed at least 18 people in a Syrian town controlled by Turkey-backed opposition fighters, activists have said.

The Britain-based Syrian Observatory for Human Rights reported that 19 people, including 13 civilians, were killed on Saturday in the town of al-Bab in Aleppo province.

The Aleppo Media Centre, an activist collective, said 15 people were killed in the blast in a busy part of town near a bus station.

Turkey’s Defence Ministry, meanwhile, said the blast killed 18 people and blamed the main Kurdish militia, known as the People’s Protection Units.

Different casualty figures are common in the immediate aftermath of explosions.

Syria car blast scene
The scene of the car bombing in al-Bab, northern Syria (Albab City via AP)

No-one has yet claimed responsibility for the attack.

A video posted online by Albab City, an activist collective, showed several vehicles on fire with black smoke billowing from a wide street with shops on both sides. Inside the bus station, several white minibuses appeared to be damaged.

“It looks like doomsday. May God help us,” a man could be heard saying as five young men carried an injured person away.

Explosions have killed and wounded scores of people in Turkish-held areas of north-eastern Syria in recent months.

Those attacks have come amid an expanding Turkish invasion of Syrian Kurdish-held towns and villages along a stretch of the border.