Security in Rome is tight as world leaders arrive for an inauguration mass for Pope Francis in St Peter’s at 09.30 on Tuesday 19 March.

The security operation in place is similar to that employed by the city for the funeral of Pope John Paul II in 2005 and Rome will become a no-fly zone on the day. To facilitate the large crowds expected, both the city's metro lines will be free of charge until 14.00 on 19 March.

Many of the expected 150 delegations are staying on Via Veneto, and their journey to the Vatican on Tuesday morning will result in the closure to traffic of streets in the city centre, in particular Via Veneto, Corso Vittorio Emanuele and Via Gregorio VII.

From 19.00 on Monday 18 March any cars parked in the St Peter’s area of Via Gregorio VII will be removed. The full traffic plan, including public transport deviations, can be seen on the website of Rome's mobility agency.

Among the major political figures attending the event are US vice president Joe Biden, German chancellor Angela Merkel, Brazilian president Dilma Rousseff, European Commission head Jose Manuel Barroso, and Zimbabwe's controversial president Robert Mugabe whose EU-wide travel ban does not include Vatican City. Mugabe last visited the Vatican in 2011 for the beatification of John Paul II.

One of the more delicate diplomatic situations that the Argentinian pope is likely to face is with the president of his own country, Cristina Kirchner. When Pope Francis was archbishop of Buenos Aires, he and Kirchner frequently clashed on issues such as gay marriage and abortion laws. The pope's meeting with Kirchner in the Vatican on 18 March will be his first meeting with a head of state.

Queen Elizabeth II of England will be represented by her cousin the Duke of Gloucester. The Anglican Communion will be represented by the Archbishop of York,  John Sentamu, because the new Archbishop of Canterbury, Justin Welby, is on a prayer journey around England before his own inauguration on 21 March.