WASHINGTON (AP) — U.S. Defense Secretary Leon Panetta, the leader of the world's largest military, is expected to meet with Pope Benedict XVI, the world's best known purveyor of peace, on Wednesday in an audience at the Vatican.

Panetta, a staunch Catholic and Italian-American, is in Rome as part of a weeklong swing across Europe meeting with defense ministers to talk about ongoing conflicts in Afghanistan and Mali. This is expected to be Panetta's last overseas trip as Pentagon chief, as he long has planned to step down once his replacement is confirmed.

Defense officials say Panetta has not yet met with Pope Benedict XVI, although he may have met with previous pontiffs. On many of his overseas trips, Panetta often will go to Catholic mass at a local church.