The Lebanese army announced a state of alert across Sidon on Monday, a day after two attacks upon checkpoints in the southern city left a soldier and four assailants dead. According to dpa, Lebanese troops, backed up by tanks, fanned out across the streets of Sidon. Lebanon's largest Palestinian refugee camp, home to 75,000 people - and reputedly a refuge for those fleeing the law - lies upon Sidon's outskirts. Meanwhile, the army released details of Sunday evening's attacks. It said that at 9 pm (1900 GMT) on Sunday, soldiers at the al-Awwali Bridge checkpoint fired upon a pedestrian who ran towards them with a hand grenade when asked for his papers. The grenade exploded, killing the attacker. Two soldiers were wounded. Two companions of the attacker fled. Shortly afterwards, troops stopped a vehicle at an army checkpoint in the Majdelyoun area. A passenger dismounted and hugged one of the soldiers as he detonated a hand grenade, killing both men. Soldiers manning the checkpoint then shot and killed the remaining two occupants of the vehicle. Lebanese President Michael Suleiman condemned the attacks as "criminal, terrorist acts."