Pope Francis arrived late for his weekly address in St. Peter's Square on Sunday, explaining that he had been stuck in an elevator in the Vatican for 25 minutes and had to be freed by firefighters.

"I have to beg your pardon," the smiling pontif said as he started the address about 10 minutes late.

He then explained that there had been a electrical power problem in the Vatican and that he had been stuck in the elevator until freed by Vatican fire officers.

"A round of applause for the fire brigade," he told the crowd.