A car bomb killed at least five people and wounded several others in a rebel-held town in northern Syria today. <br/><br/>The Syrian Observatory for Human Rights said, the dead were four civilians and a police officer. Toll could rise because a number of those wounded are in serious condition. <br/><br/>The blast littered the ground with debris and set an enormous fire that sent thick clouds of black smoke billowing into the air. Civil defence workers and residents tried to put out the blaze. More than 320,000 people have been killed in Syria since the conflict began in March 2011 with anti-government protests.