VATICAN CITY — Pope Benedict XVI will break with tradition this year and celebrate Christmas Eve Mass in St. Peter's Basilica at 10 p.m. instead of midnight.

Papal spokesman the Rev. Federico Lombardi told The Associated Press the decision to change the schedule was made two months ago to "ease the (pope's) fatigue at a time when there are many ceremonies and commitments" during Christmas holidays.

"There's no cause for worry about the health" of the 82-year-old Benedict, Lombardi said. Vatican aides decided to "stretch out" his strength and the pontiff agreed, the spokesman added.

On noon Christmas Day Benedict will read a traditional holiday message from the central balcony of the basilica as crowds gather in the square. The message "Urbi et Orbi" (Latin for to the City and to the World) usually contemplates the religious significance of Christmas and reflects on wars, disasters and other world events.

The pontiff will mark the year's end with a solemn Vespers service of thanksgiving at 6 p.m. Dec. 31 in the basilica. On New Year's Day he will return to the basilica to celebrate Mass at 10 a.m. He will lead a Mass at the same hour in St. Peter's on Jan. 6, the feast day of the Epiphany.