The TV says the car blew up on the western edge of the town of Qamishli, near the Turkish border today.
The Britain-based Syrian Observatory for Human Rights says the explosion targeted a centre of the local Kurdish police and a nearby government building.
No one immediately claimed responsibility for the attack but the Islamic State group has carried out several bombings in Kurdish areas in Syria in the past.
The predominantly Kurdish US-backed Syria Democratic Forces have been the main force fighting IS in northern Syria and have captured wide areas from the extremists.