"The Holy Father died this evening at 9:37pm in his private apartment. All the procedures outlined in the apostolic Constitution, Universi Dominici Gregis, that was written by John Paul II on 22 February 1996, have been put in motion."
The announcement came from papal spokesman Joaquin Navarro-Valls and was distributed to journalists via email.
The Pope died on Saturday after suffering heart and kidney failure following two hospitalisations in as many months.
Just a few hours earlier, the Vatican had said he was in a very serious condition but had responded to members of the papal household.
Italy in grief
The news was immediately announced to about 60,000 people gathered in St Peter's Square and was met with a long applause, an Italian sign of respect. Bells tolled and many people wept openly.
"Our Holy Father John Paul has returned to the house of the Father," Archbishop Leonardo Sandri told the crowd.
The Pope was already racked by arthritis and Parkinson's disease, his voice often reduced to a raspy whisper.
The news was met with long
applause in St Peter's Square
The conclave to elect a new pope will start in 15 to 20 days, with 117 cardinals from around the world gathering in the Vatican's Sistine Chapel to choose a successor.
There is no favourite candidate to take over. Karol Wojtyla was himself regarded as an outsider when he was elevated to the papacy on 16 October 1978.
Since his surprise election in 1978, John Paul II travelled the world frequently, staunchly opposing communism in his native Poland and across the Soviet bloc, but also preaching against rampant consumerism, contraception and abortion.
He was a robust 58-year-old when the cardinals stunned the world and elected the cardinal from Krakow, the first non-Italian pope in 455 years.
In his later years, however, John Paul II was the picture of frailty, weighed down by ailments. Although he kept up his travels, he became too weak to kiss the ground.
A fierce enemy of communism, he set off the sparks that helped bring down communism in Poland, from where a virtual revolution spread across the Soviet bloc. No less an authority than former Soviet President Mikhail Gorbachev said much of the credit went to John Paul II.
At the same time, John Paul II was no friend of Western lifestyles, warning against rampant consumerism and casual