Security sources said the blast had caused a number of injuries. An arms depot of the Iran-backed Shi'ite Muslim group Hezbollah exploded in southern Lebanon on Tuesday, a security source said, injuring several people and sending a new shockwave across a nation grappling with its deepest crisis in three decades. The security source said the arms depot blast, which sent a huge column of black smoke into the sky, was caused by a "technical error." The al-Manar television station run by Lebanon's Hezbollah said the cause of an explosion in southern Lebanon on Tuesday was not yet clear. The explosion...