Thousands Pack St. Peter's Square for Pope Francis' Inaugural Mass

L'Osservatore Romano/Getty Images(VATICAN CITY) -- Hundreds of thousands of people filled St. Peter's Square on Tuesday to welcome Pope Francis, the first Latin American pontiff, and celebrate his inaugural mass in front of numerous heads of state from around the world.

The 76-year-old Argentine rode around the square in an open-air jeep as he waved and kissed babies along the way. He exited the jeep at one point to bless a man who was in a wheelchair.

Francis, dressed simply in the papal white cassock, arrived in St. Peter's Square earlier than expected. More than 340,000 people jammed into the square, according to Italian radio reports.

People began flooding into St. Peter's square since 6:30 a.m. local time, more than two hours before Pope Francis was scheduled to arrive.

During the lengthy ceremony Tuesday, Francis will receive the Ring of the Fisherman and the pallium, a special circular strip of cloth. In addition, the cardinals will make an act of obedience to the new pontiff.

The ceremony will be attended by numerous heads of state from around the world. Delegations from 132 countries are in Rome for the event, according to the Vatican.

The largest delegation, consisting of 19 people, comes from the pope's homeland of Argentina. The pope's fellow Argentine, the country's president, Cristina Kirchner, will be in attendance. The two countrymen, who have clashed in the past on social issues, held a lunchtime meeting on Monday.

Vice President Joe Biden, who is Catholic, will represent the United States at the event. He flew into Rome on Sunday evening.