BEIRUT, Lebanon , May 21 (UPI) -- The Lebanese and Palestinian presidents agreed Wednesday to support Beirut's efforts to enforce the state's monopoly on weapons by disarming Palestinian factions, preventing the use of Lebanese territory for attacks on Israel and enhancing cooperation to combat terrorism and extremism in refugee camps. A joint communique issued after Palestinian President Mahmoud Abbas met with his Lebanese counterpart, Joseph Aoun, shortly after arriving in Beirut for a three-