Pope Benedict has called for world peace and condemned inequalities between the rich and the poor in a New Year's Day Mass.
The pontiff spoke out against what he called "unregulated financial capitalism" in his address from St. Peter's Basilica Tuesday, marking the church's world day of peace.
Other world leaders who have delivered New Year's messages include Russian President Vladimir Putin. He urged Russians to work together, "move confidently forward," and withstand challenges in 2013.
In a surprise broadcast address, North Korean leader Kim Jong Un said an important issue this year would be removing confrontations between his country and South Korea. He also spoke of building his nation's economy.
Fireworks explode in the sky over downtown Grozny, the capital of Chechnya, southern Russia, January 1, 2013.
N. Korean leader Kim Jong Un makes his first New Year's speech calling for his country to focus on economic improvements with the same urgency that scientists put into the launch of a long-range rocket last month, January 1, 2013.
A security guard stands behind a New Year signboard at Burma's first public New Year countdown celebrations, Rangoon, December 31, 2012.
Kenyan children ride a carousel as families gather to celebrate the new year at Uhuru Park, Nairobi, Kenya, January 1, 2013.
Supporters of Venezuelan President Hugo Chavez pray during a mass in Caracas, December 31, 2012.
Burma's President Thein Sein called for more trust between the government and citizens. He said the world has been "amazed" by his country's political progress, following its transition from military rule.
President Mwai Kibaki marked the New Year by calling for peaceful elections in Kenya, where tensions have been rising ahead of the March 2013 general elections. He said peaceful polling would send a message to the world that Kenya is a "beacon of democracy, freedom and liberty."
In Venezuela, citizens gathered in churches and plazas to pray for ailing President Hugo Chavez, following word that he was suffering from new complications after having surgery last month.
Chavez, who has been battling cancer, is said to be suffering from a respiratory infection.