BEIRUT - At least 10 people were killed and dozens were injured by a car bomb on Thursday which targeted a building used by a rebel group in the northern Syrian town of Azaz near the Turkish border, the Syrian Observatory for Human Rights said. Yasser al-Yousef, from the political office of the Nour al-Din al-Zinki rebel group which controls the building, put the death toll higher at 25. It said the car bomb targeted a security office belonging to the group. Azaz, controlled by rebel groups, has been the scene of infighting between the various insurgent groups.