Pope Francis and U.S. President Barack Obama met for 50 minutes on Thursday at the Vatican.
The meeting lasted more than the 30 minutes that most of the pope's conversations with heads of state and government run.
The pontiff and the U.S. leader exchanged presents and introduced their delegations.
Obama met with Vatican Secretary of State Pietro Parolin, who had a long meeting at the Vatican with his U.S. counterpart, John Kerry, in January.
Kerry also participated in Thursday's meeting at the Vatican.
Obama left the Vatican at 12:20 p.m., two hours after his arrival, and headed for the Quirinal Palace, the official residence of Italy's president.
The U.S. president and Italian President Giorgio Napolitano had lunch at the palace.
The meeting between Obama and Pope Francis started at 10:30 a.m., when the first pontiff from Latin America welcomed the U.S. president in the Sala del Tronetto (Little Throne Room), next to the library.
The two men posed briefly for photographers and then went into the library, where they sat across from each other.
"Welcome, mister president," the pope said in English.
Reporters and photographers were asked to leave the room after a few minutes and the two leaders started their private meeting with the assistance of two interpreters.
Obama is scheduled to meet with Italian Prime Minister Matteo Renzi after his lunch with Napolitano. EFE