Vatican City:
Cardinals prayed in St Peter's Basilica on Tuesday ahead of a conclave to elect the next pope with no clear frontrunner after Benedict XVI's historic resignation as leader of the world's 1.2 billion Catholics left behind a Church beset by scandals.
The 115 scarlet-robed cardinals who will take part in the rare papal election in the Sistine Chapel starting later on Tuesday entered the church packed with thousands of pilgrims in a solemn procession to begin the special mass.
The cardinals had moved into the Vatican earlier in the day, where they will live cut off from the outside world until they have made their choice.
Cardinals took to Twitter to say their last goodbyes to their online flock before the conclave, where jamming devices will block any communications.
"Last tweet before conclave: May Our Father hear and answer with love and mercy all prayers and sacrifices offered for fruitful outcome. God bless!" South African cardinal Wilfrid Napier said.
The cardinals will be sworn to secrecy with a solemn oath that threatens anyone who reveals the contents of their deliberations with excommunication.
They will enter the Sistine Chapel in a procession as part of a centuries-old ritual, chanting in Latin to invoke divine guidance for the vote.
The cardinals are then set to hold a first round of voting -- but the Vatican has already said it expects the smoke from the burning of the ballots in a special stove in the chapel to be black, indicating no pope has been elected.
From Wednesday, ballots will usually be burnt at around 1100 GMT after two rounds of voting in the morning and at around 1800 GMT after two rounds in the afternoon -- the smoke above the Vatican is famously turned white if there is a new pope.
Conclaves normally last no more than a few days and a two-thirds majority is required.
"The Church is like a boat, all the faithful are sailing in it together but we're without a helmsman at the moment," said Celestina, 62, a nun from Croatia, praying in a church near the Vatican.
Among the possible candidates, three have emerged as favourites -- Italy's Angelo Scola, Brazil's Odilo Scherer and Canada's Marc Ouellet, all of them conservatives cast in the same mould as "pope emeritus" Benedict XVI.
But the rumour mill in the Vatican has thrown up more names including cardinals from Austria, Hungary, Mexico, the Philippines, South Africa and the United States -- many of them inspiring pastoral figures in their communities.
Mexican cardinal Norberto Rivera Carrera told Italian daily La Stampa that there was no agreement yet among the cardinal electors on what type of candidate they wanted.
"Some imagine him to be more academic, able to establish a dialogue with culture. Others ask for someone who is close to the people. Others still want someone with more authority to put some Church problems in order," he said.
"So far, there is no majority," he said.
Although the field is wide open, a few key aims unite many of the cardinals -- reforming the intrigue-ridden Vatican bureaucracy, countering rising secularism in the West and re-igniting Catholic faith in the way Benedict's charismatic predecessor John Paul II did.
The scandal over decades of sexual abuse of children by paedophile priests -- and the efforts made by senior prelates to cover up the crimes -- has cast a long shadow over the Church that will be an ongoing challenge for the new pope.
British cardinal Keith O'Brien had threatened to overshadow the conclave after claims surfaced of sexual misconduct with priests and seminarians in the 1980s, but the prelate quickly withdrew before cardinals gathered in Rome.
There have been calls too from within the Church for a rethink of some basic tenets such as priestly celibacy, the uniform ban on artificial contraception and even allowing women to be priests as in other Christian denominations.
"We need someone able to provide the Church with what it needs in today's world," said Roger Seogo, a priest from Burkina Faso visiting the Vatican.
A series of pre-conclave meetings of cardinals last week offered a rare chance to air grievances against the Vatican, and Italian media on Tuesday reported a clash between two cardinals in one meeting over the future of the Vatican's scandal-tainted bank, which is struggling for international approval.
The tradition of holding conclaves goes back to the 13th century when cardinals were locked into the papal palace in Viterbo near Rome by a crowd of angry townspeople because they were taking too long to choose a pope.
That conclave still dragged on for nearly three years but the rules have been reworked since then and the longest conclave in the past century -- in 1922 -- lasted only five days. Benedict's election took just two days.
Benedict stunned the world on February 11, announcing that he no longer had the strength of body and mind to keep up with a fast-changing modern world.
In a series of emotional farewells attended by tens of thousands of supporters, 85-year-old Benedict said he would live "hidden from the world" and wanted only to be "a simple pilgrim" on life's last journey.
Vatican experts have said the German's decision, which makes him only the second pope to resign by choice in the Church's 2,000-year history, could mean future popes will also step down once their health fails.