Pope Francis has presided over a solemn prayer service in St. Peter's Basilica on New Year's Eve, using his homily to stress life's fleetingness.

The spiritual leader said, "How we like to be surrounded by so many fireworks, seemingly beautiful, but which in reality last only a few minutes."

As humans, he said, there is a "time to be born and a time to die" and New Year's also is a time to reflect on our mortality, "the end of the path of life."

Afterward, the 78-year-old pontiff, wearing a long white coat, a scarf and a thin skull cap, braved frigid air to admire the life-size Nativity scene in St. Peter's Square. For 20 minutes, he walked around shaking hands of people lined up behind barriers to greet him.