ISTANBUL - Pope Leo will meet in Turkey on Friday with Christian leaders from across the Middle East, and is expected to urge unity among denominations divided for centuries during his first overseas trip as leader of the global Catholic Church.

The first U.S. pope will attend a celebration for the 1,700th anniversary of a landmark early Church council, held in modern Turkey. It produced the Nicene Creed, still used by most of the world's 2.6 billion Christians today.