Four people were killed on Monday in a car bomb blast targeting a military bus on the outskirts of the restive northern Lebanese port city of Tripoli, security and military officials said. The attack risks further undermining stability in the troubled country and efforts to reconcile rival political factions."Three of the casualties were soldiers," as were 24 of the 30 wounded, a military said. Earlier, a security official had said six people were killed in the attack, the second deadly bombing targeting the Lebanese military in two months. The bomb, placed under a parked car at the southern entrance to the city, was packed with nuts and bolts and police suspect the device was detonated by remote control. It blew up as the bus was heading towards the capital Beirut during morning rush-hour, a military spokesman said. There were about 24 passengers on board. Police and the army cordoned off the area as forensic experts began gathering evidence while residents rushed to the scene or to nearby hospitals to look for their loved ones.One man in his 50s wept and appealed for news about his son who he said was on board the bus. The force of the blast shattered windows and damaged cars nearby. The vehicle under which the bomb was placed was left a burned-out pile of twisted metal. "This attack is targeting security and stability in the country, undermining the reconciliation efforts that are taking place," the army spokesman said. Other officials said they suspect the attack was aimed at undercutting the army's bid to secure Tripoli, which has has been rocked by deadly sectarian violence in recent months.Interior Minister Ziad Baroud called for an emergency meeting of security services to discuss the situation following the blast.Tensions in the city have eased in the past few weeks after Lebanon's rival factions signed a reconciliation accord aimed at putting the lid on a political crisis that took the country to the brink of a new civil war earlier this year."This attack targets the army's morale and seeks to rattle relations between the military and the residents of Tripoli... following the expanded deployment of troops," Tripoli MP Moustapha Alloush said.