In this war, many Palestinian camps were attacked and massacres such as the Karentina massacre and the Tel Zater camp massacre were perpetrated. He participated in military operations after receiving military training (the "Karameh Course"), in Beirut, 1976, where he volunteered to fight in southern Lebanon and fought in the Battle of Kfarshoba in January 1976 against the Israeli army. He was elected as a member of the command of the South Beirut Front (Al-Shayyah - Ein al-Ramana) in the Joint Palestinian-Lebanese Forces in 1976, and took charge of several military hubs in the South Beirut area: Maroon Musk, Marmkhail Church, Aboulloy - Rosalie War. In June 1976, Manasirah led the Battle of the Mills, with to ease the siege of the Tel Zaater camp, which was destroyed on 12 August 1976 and abandoned its people. At the time of the Israeli invasion of Lebanon in 1982, his awareness-raising activities were restricted to the newspaper Battle, but he fought in the Battle of the Museum in August 1982 during the Siege of Beirut. He recounted the details of the first phase of the Lebanese Civil War in the book The Lovers of Sand and Manares. At the end of the Lebanese phase of the organization and the work of the armed forces, as well as of the supporters, a deal was signed through an American-Arab mediation for the exit of Al-Mutama and the Palestinian guerrillas in exchange for the cessation of Israeli bombardment and the safety of the camps following the exit of the militants. He then left on a Greek ship by sea to Tartus, Syria, with the forces of the Palestine Liberation Organization (PLO).