A car bombing in a rebel-held northwestern town in Syria killed at least 12 people and wounded dozens on Monday, setting cars on fire and sending people running in panic, two activist groups said.

It said dozens of people were wounded by the explosion in the market of Darkoush, a small rebel-controlled town near the Turkish border, and some of them were taken into Turkey for treatment.

The car bomb went off at a market in the town of Darkoush in Idlib province, according to the Britain-based Syrian Observatory for Human Rights and the Local Coordination Committees (LCC).

The groups, which rely on a network of activists on the ground, differed on the number of those killed in Monday's bombing - which is often the case in the immediate aftermath of big attacks. The Observatory said 20 people died while the Committees said at least 12 were killed.

An amateur video posted on the LCC's Facebook page showed several cars on fire in a street full of debris. People are seen running in panic as smoke billows from the area, and several shops and apartment buildings appear heavily damaged in the blast. Another video shows men carrying two bodies and placing them in a blanket. The videos appeared genuine and corresponded to other AP reporting on the events depicted.

Car bombs are becoming more common in Syria's civil war, now in its third year. The conflict has killed more than 100,000 people.

On Sunday, two car bombs exploded near the state TV building in Damascus. The SANA news agency said the TV's headquarters in Umayyad Square was damaged in the blast, but there was no word on casualties.

The Damascus attack came just hours after gunmen abducted six Red Cross workers and a Syrian Red Crescent volunteer after stopping their convoy early Sunday in northwestern Syria, a spokesman said, in the latest high-profile kidnapping in the country's civil war.

Much of the countryside in Idlib province, as well as the rest of northern Syria, has fallen over the past year into the hands of rebels, many of them Islamic extremists, and kidnappings have become rife, particularly of aid workers and foreign journalists.

In other developments, Syrian lost power Monday in several regions in the country's center as well as areas on the Mediterranean coast but there was no indication if the power cut was related to the conflict or result of sabotage.

SANA quoted Minister of Electricity Imad Khamis as saying that a malfunction at a power station had caused the outage. Khamis said maintenance work was underway and that power will gradually return in the coming hours.