The three-day visit, starting Friday, comes at a time of turmoil in the region -- the civil war in neighboring Syria and in the aftermath of a mob attack that killed several Americans in Libya, including the U.S. ambassador.
The Pope told reporters on the plane that imports of weapons to Syria is a "grave sin."
The visit brings the pope to the nation with the largest percentage of Christians in the Mideast -- nearly 40 percent of Lebanon's 4 million people, with Maronite Catholics the largest sect.
Lebanese authorities are enacting stringent security measures, suspending weapons permits except for politicians' bodyguards and confining the visit to central Lebanon and the northern Christian areas.
