Vatican City, March 18 - Pope Francis will kick off the inaugural mass to mark the start of the new pontificate with a long tour around St. Peter's Square, Vatican Spokesman Father Federico Lombardi told journalists at a two-hour briefing in the Vatican on Monday. Pope Francis's tour in the pope-mobile is expected to last from about 8:45 local time until the beginning of mass at about 9:30, a celebration Lombardi said would be marked by "simplicity". The religious celebration will begin at St. Peter's tomb, where the Piscatory ring and the Pallium woolen vestment of the papal office will be conferred to the new pope. Pope Francis, formerly Jorge Mario Bergoglio, chose a model of Piscatory ring made of gold-plated silver designed by the late Enrico Manfrini, who died in 2004. The Piscatory ring, or Ring of the Fisherman, is typically cast in gold for each pope, and depicts St. Peter fishing from the side of a boat. It served as the official signet to seal papal documents until 1842. No procession to the offertory will be made. The Gospel will be sung only in Greek, and not in Latin. Communion will be given by the deacons of the church square - not by the pope - and by another 500 priests in St. Peter's Square. Father Lombardi said 132 country delegations and international organizations had indicated their presence at Tuesday's inaugural mass, which will be packed with high officials and heads of state. The 16 people of the Italian delegation include President Giorgio Napolitano, outgoing Premier Mario Monti, the president of the Italian Constitutional Court, and the newly elected speakers of the Italian Chamber and Senate. Argentinian President Cristina Fernandez de Kirchner flew in for the mass and was received in a private audience on Monday. Prior to becoming pope, Bergoglio had been known to criticize Kirchner in his office as archbishop of Buenos Aires. US Vice President Joe Biden, a Catholic, is representing his country at the inauguration as President Barack Obama is on an official visit to Israel. French Premier Jean-Marc Ayrault and Foreign Minister Laurent Fabius are attending in the French delegation. Egyptian Culture Minister Mohamed Saber Arab will also be present. The Serbian Orthodox Church is sending Metropolitan of Montenegro and the Littoral Amfilohije Radovic', the Serb patriarch announced from Belgrade. No special invitations were sent out to foreign delegations for the inauguration, Lombardi said. "There is an appointment set and those who choose to come are welcome," he said. International delegates arriving in Rome for Tuesday's election of Benedict XVI's successor include the controversial leader of Zimbabwe, Robert Mugabe, defying an EU travel ban. "Those who are coming wanted to come and no one has said otherwise. There are no privileged (guests)," Lombardi said. Security in Rome's airports and throughout the city is on high alert. At Fiumicino airport alone, more than 80 heads of state, ministers, ambassadors and religious figures are expected to arrive between 7am and 11pm local time on Monday, Italy's national civil aviation agency Enac said. East Timor President Taur Matan Ruak and Taiwan President Ying Jeou Ma arrived early Monday, along with Uruguay leader Danilo Astori and U.S. Senator Cris Smith. German Chancellor Angela Merkel, European Commission President Jose' Manuel Barroso, and King Albert II and Queen Paola of Belgium are to arrive at Rome's second airport Ciampino.