The Vatican is preparing for a huge crowd for Pope Francis' inaugural mass tomorrow.

The event will bring together European royalty, heads of state and world spiritual leaders in Rome.

Hundreds of thousands of people are expected to fill St Peter's Square and surrounding streets for the mass to formally install Francis as the new leader of the world's 1.2 billion Roman Catholics.

The crowd may be the biggest in Rome since more than 1.5m people went to the city for the beatification of the late Pope John Paul II on 1 May, 2011.

Earlier, Argentinian President Cristina Fernandez asked Pope Francis to intervene in support of Buenos Aires in a dispute with Britain over the Falkland Islands in the South Atlantic.

Ms Fernandez had lunch with the former Buenos Aires Archbishop Jorge Bergoglio in the Vatican shortly after arriving in Rome.

She told reporters afterwards: "I asked for his intervention to avoid problems that could emerge from the militarisation of Great Britain in the south Atlantic.

"We want a dialogue and that's why we asked the Pope to intervene so that the dialogue is successful."

British Prime Minister David Cameron said last week that Pope Francis had been wrong to say in 2012 that Britain had "usurped" the disputed islands from Argentina.