Pope Benedict XVI beatified John Paul II before more than a million faithful in St. Peter's Square and surrounding streets Sunday, moving the beloved former pontiff one step closer to possible sainthood.

The crowd erupted in cheers, tears and applause as an enormous photo of a smiling John Paul was unveiled over the loggia of St. Peter's Basilica and a choir launched into a hymn long associated with the Polish-born pope.

The beatification, the fastest in modern times, is a morale boost for a church scarred by the sex abuse crisis, but it has also triggered a new wave of anger from victims because the scandal occurred under John Paul's 27-year watch.

Benedict pronounced John Paul "Blessed" shortly after the start of the Mass, held under sunny skies and amid a sea of Poland's red and white flags.

Benedict then received a silver reliquary holding a vial of blood taken from John Paul during his final hospitalization. The relic, a key feature of beatification ceremonies, will be available for the faithful to venerate.

It was presented to him by Sister Tobiana, the Polish nun who tended to John Paul during his pontificate, and Sister Marie Simone-Pierre of France, whose inexplicable recovery from Parkinson's disease was decreed to be the miracle necessary for John Paul to be beatified.

Police placed wide swaths of Rome, even kilometres from the Vatican, off limits to private cars to ensure security for some of the estimated 16 heads of state and five members of European royalty attending.\

Pope Benedict XVI drives through the crowd as he arrives for the beatification of the late pope John Paul II in St. Peter's Square. Anja Niedringhaus/Associated Press

Spain's Crown Prince Felipe and Princess Letizia, wearing a black lace mantilla, mingled with Italian Premier Silvio Berlusconi, Poland's Solidarity leader Lech Walesa and Zimbabwean President Robert Mugabe, who sidestepped an EU travel ban to attend.

Helicopters flew overhead, police boats patrolled the nearby Tiber River and some 5,000 uniformed troops patrolled police barricades to ensure priests, official delegations and those with coveted VIP passes could get to their places.

Thousands of pilgrims, many of them from John Paul's native Poland, spent the night in sleeping bags on bridges and in piazzas around town, and then packed St. Peter's as soon as the barricades opened over an hour in advance because the crowds were too great.

They stood shoulder-to-shoulder on the main boulevard leading to the Vatican, Via della Conciliazione, as well as on side streets around it and the bridges crossing the Tiber leading to St. Peter's. Rome police headquarters put the number attending at over a million.

"John Paul was a wonderful man and it's a privilege to be here. It's wonderful to see people from all across the world," said Anne Honiball, 48, a nursing home administrator from Worthing, England who carried a small Union Jack flag.

"We missed the royal wedding but we are Catholics and this was a bit more important, I suppose," said Honibal, a former Protestant who converted to Catholicism 10 years ago.

It's the fastest beatification on record, coming just six years after John Paul died and beating out the beatification of Mother Teresa by a few days.

Benedict put John Paul on the fast-track for possible sainthood when he dispensed with the traditional five-year waiting period and allowed the beatification process to begin weeks after his April 2, 2005, death. Benedict was responding to chants of "Santo Subito" or "Sainthood Immediately" which erupted during John Paul's funeral.