The Britain-based Syrian Observatory for Human Rights said the bombing occurred today near the town of Salamiya in the central province of Hama.
A Syrian government official also confirmed the bombing but could not immediately confirm the death toll. He spoke on condition of anonymity because he wasn't authorised to speak to the media.
Syrian rebels, particularly those belonging to hard-line Sunni groups, use car bombings to target forces loyal to Syrian President Bashar Assad. There has been fierce fighting in the area around Salamiya for weeks.