In a ritual that has not been altered for centuries, bells tolled mournfully in the Vatican to mark the demise of the 84-year-old pontiff. They were soon being echoed by bells all over Rome.

The death, at 9.37pm local time, was confirmed by the Spanish cardinal Eduardo Martinez Somalo, the papal chamberlain, and announced within minutes by Joaquin Navarro-Valls, the Pope's official spokesman, who distributed the news to journalists via e-mail.

A formal announcement that followed from Archbishop Leonardo Sandri, the Vatican's undersecretary of state, was heard in silence by 70,000 in the square. "Our Holy Father, John Paul, has returned to the house of the Father," he said. "We all feel like orphans this evening."

Some of the crowd then broke into applause for the life of the Pope; others sobbed uncontrollably at his passing.

As the end approached, history's best travelled and third longest serving pontiff had urged his followers not to cry for him by dictating a message to his secretary.

"I am happy and you should be happy too," he said. "Do not weep. Let us pray together with joy."

His last moments were described early today by Father Jarek Cielecki, director of Vatican Service News, a Catholic TV channel. "The Holy Father died looking towards the window as he prayed, and that shows that in some way he was conscious," Cielecki said.

"A short while before dying, the Pope raised his right hand in a clear, although simply hinted at, gesture of blessing, as if he became aware of the crowd of faithful present in St Peter's Square, who in those moments were following the reciting of the Rosary," he added.

"Just after the prayer ended, the Pope made a huge effort and pronounced the word 'Amen'. A moment later, he died."

The official spokesman said the Last Rites had been administered again during a mass that began at 8pm. Fourteen people were present in the room as he died, including Archbishop Stanislao Dziwisz, his personal secretary, who had been with him for 40 years.

According to an unofficial report, the Pope died holding the archbishop's hand.

The chamberlain followed the prescribed ritual of calling the Pope's baptismal name, Karol, three times, ostensibly to make certain of his death. Another official pulled the Fisherman's Ring, symbol of papal power, from his finger.

The great door at St Peter's Basilica was closed and will remain so until white smoke issues from the Sistine Chapel to signify the election of a successor. Three days of national mourning were declared by the Italian government and Vatican flags flew at half-mast. The Pope's appeal for composure did not prevent a wave of grief from sweeping over St Peter's Square, where a huge crowd of well-wishers had been praying for him. John Paul had led the church for 26 years. He was the only pope many of his followers had known.

In his native Poland, people fell to their knees as the news reached them in Krakow, where he had entered the priesthood and served as archbishop. Ambulances were called for mourners in shock.

After surviving a would-be assassin's bullets and various injuries and illnesses, the Pope's death had been forecast for more than a decade and many of the figures tipped to succeed him have died. Yet however frail in his final years, he packed more into his reign than most of his predecessors and will be remembered for a series of unprecedented and highly symbolic gestures.

Apart from travelling to more countries than any other pope, creating more saints than any other and personally making contact with more people than anyone in history, he was also the first reigning pope ever to travel to Britain, where he met the Queen and knelt in prayer with Robert Runcie, the then Archbishop of Canterbury in Canterbury Cathedral. He was the first pope to visit the synagogue of Rome.

He also wrote books and poetry. "He was a great man," said Florence Magnant, a silver-haired nun from Bordeaux who had come to St Peter's Square to offer up prayers for a man remembered in his native Poland by his nickname of "Lolek".

Tributes and messages of condolence poured in from all over the world. Some remembered the Pope as a champion of the defeat of Soviet communism in the late 20th century. In America, whose conservative administration appreciated his fervent opposition to abortion and gay marriage — if not his opposition to the war in Iraq — he was hailed as a man of "greatness".

The health of the Pope, who for years had suffered from Parkinson's disease, had declined abruptly on Thursday when, on top of breathing problems, he developed a high fever brought on by a urinary infection. He suffered heart and kidney failure, and slipped in and out of consciousness after announcing his preference not to be taken to hospital. His exhortation, "Do not weep", gave heart to his aides and seemed to echo his first words to the faithful in St Peter's Square on his election as Pope in 1978 when he told the crowd: "Be not afraid."

Many Catholics found it hard to imagine the future without him, but even as he lay dying cardinals were arriving in Rome from all over the world in readiness for a conclave in the Sistine Chapel to elect a new leader.

The conclave must begin at least 15 days after the death of a pope — but not more than 20 — and the cardinals are deprived of all contact with the outside world until a new pope is elected.

Each vote is followed by the burning of ballot papers with chemicals to make black or white smoke, white smoke signalling that a cardinal has won the two-thirds of the votes necessary to be elected.

The Italians are said to be keen to regain the papacy but there is a Latin American camp as well as an African lobby. In the jockeying to succeed John Paul, however, any papabile, as a papal contender is known, is advised to keep a low profile. According to a Vatican saying, “He who enters the conclave as a papabile exits a cardinal.”

Age could be the determining factor, with an older candidate likely to be favoured. According to Vatican sources, the feeling in the conclave might be that John Paul’s papacy went on for too long.

Among his friends and advisers there was relief that his suffering was over. After undergoing surgery last month on his throat, he had endured anguish as he tried in vain to give an Easter blessing to a crowd of thousands only to find that no sound came from his mouth.Having lost the ability to swallow, he was being fed through a tube.

On Friday, cardinals who visited him were moved by his courage and strength but also upset by his suffering. “It was very sad for me to see him that way,” said Edmund Szoka, a Polish-American cardinal and governor of Vatican City. “It must have been terrible suffering to have to keep gasping for breath. He was completely alert but couldn’t speak. I knelt down by the bed and kissed his hand and told him I was praying for him.”

The funeral is expected to be held by Friday at the latest. It is unclear, however, exactly where he will be buried. There has been speculation that he had expressed a preference for his body to be returned to Krakow’s Wavel Cathedral.

After the death of John Paul I in 1978, an estimated 750,000 mourners filed past the body over three days. Many more could pay homage to his successor, who won the affection of the globe with his familiar refrain of “God loves you all”, his habit of kissing the tarmac upon arrival in any new country, and his call to value the aged, respect the sick and love the poor.

“We’ve come to pay our respects,” said 32-year-old James Meikle, a Londoner who works for a property company in Rome. He and his wife, Kate, are Anglicans but admired the Pope for his success in reaching out to different cultures.

A group of Indian men who stood nearby in St Peter’s Square seemed to endorse that. They had spent the previous night sleeping there in a show of concern for the Pope. “He is the friend of the poor, the friend of the sick and the friend of the little,” said one, who identified himself only as John. “We think of him as our father.”

Many brought flowers to deposit in the square. Vatican policemen in black suits with red stripes kept a wary watch.

Michael Magee, a papal official, said just before the death was announced: “What is going on is awesome. It is something very sad and yet joyful and full of reverence. It is tragic but in a sense there is this great sense of completion.”

In Wadowice, the southern Polish town where the Pope was born, people left school and work early and headed to church to pray for a native son they remembered as a sporting figure who enjoyed playing football and skiing.

“I am losing my friend, my neighbour,” said Eugeniusz Mroz, a former classmate of the Pope. “It is the biggest tragedy in my life.”