Seven people were injured when an explosion aboard a parked bus rocked Sad al-Boshariyeh Monday, an area east of Beirut, Lebanese police said, according to dpa. The explosion occurred in a mainly Christian area and near a church, police said without elaborating. This is the fourth explosion to rock Beirut since May 20 when fighting broke out between the Lebanese army and the al-Qaeda inspired movement Fatah al-Islam in northern Lebanon. The group has threatened to take the battles outside the camp.