Pope John Paul II (search), his heart and kidneys failing, was near the end as the sun rose over the Vatican early Saturday.

In St. Peter's Square (search), the sprawling plaza adjacent to the pope's quarters, as many as 70,000 people gathered Friday evening to pray and stand vigil through the chilly night. At one point they were greeted by Angelo Comastri, the pope's vicar general for Vatican City.

"This evening or this night, Christ opens the door to the pope," Comastri told the crowd.

At times St. Peter's Square fell so silent the sound of the water trickling from fountains could be heard. At other times, the crowd sang, "Stay with us!"

But as the night wore on, the crowd thinned out, and only about 100 were left at daybreak. Many of the remaining faithful huddled in blankets and kept their eyes on John Paul's third-floor windows, where the lights remained on in the pope's studio and his secretary's room. The papal bedroom was not lit.

A message written with prayer candles placed on the ground read "con te" — with you.

In a sign of the pope's decline, several cardinals said they were heading to Rome, including Roger Mahony, archbishop of Los Angeles, and William Keeler, archbishop of Baltimore, Maryland. After the official mourning period following the death of the pope, cardinals hold a secret vote in the Sistine Chapel to choose a successor.

The pope "is on the verge of death," Cardinal Javier Lozano Barragan (search), head of the Vatican's health care office, told the Mexican television network Televisa on Friday evening. "I talked to the doctors and they told me there is no more hope."

Newspapers in Italy devoted most of their Saturday editions to the suffering of the 84-year-old pope. Il Tempo showed a photo of the white-clad pontiff with his back turned to the camera, with the headline, "Ciao, Karol."

The Il Secolo XIX newspaper of Genoa reported that the pope, with the help of his private secretary Archbishop Stanislaw Dziwisz (search), wrote a note to his aides urging them not to weep for him.

"I am happy, and you should be as well," the note reportedly said. "Let us pray together with joy."

In Kuria Square in Krakow, Poland, other supporters gathered outside a yellow house where the pope once lived for a vigil Mass, and they paid tribute in his birth town of Wadowice. And in the United States, churches across the country held their own Masses for Pope John Paul II.

Earlier, a large Mass was held for him by the Vatican in a nearby basilica, along with others around the world, after news spread of the pontiff's worsening health. He received the Roman Catholic sacrament administered to the very ill and dying — called "Last Rites" in the past — on Thursday.

Also Friday evening, Italian media backed away from reports that the pope had died.

Some Italian wire and television sources reported just before 9 p.m. Rome time that the pontiff's heart and brain activity had stopped and a monitor on a machine had displayed a flatline, but they reversed that proclamation after Vatican sources said it wasn't true and there was no such machine in the pope's apartment.

Earlier Friday, the pope lost consciousness, his breathing was shallow and his kidneys were also apparently failing. He slipped in and out of a coma overnight Thursday, according to Italian media reports.

The Vatican issued an official statement addressing some of the evening's turn of events.

"The general condition and cardio respiratory condition of the Holy Father have further worsened," said the statement, issued just after 7 p.m. (noon EST) Friday. The Vatican also said the pope's breathing had become shallow.

There was no scheduled time for another statement, though the Vatican press office was expected to reopen at 9 a.m. (2 a.m. EST).

As the medical developments unfolded, the pope's followers attended a large Mass for him at the church of Santa Giovanni in Laterano in Rome, led by Cardinal Camillo Ruini, the pope's vicar, who is charged with making the formal announcement of the pope's death when it occurs.

"Give him the strength he needs at this moment in his life ... Amen," prayed Ruini.

The Vatican reported that the "Holy Father, with visual participation, is joining in the prayers of those assisting him."

Meanwhile, people continued to stream in to join the Mass and pay their respects to their pope.

"The pope's faith is so strong and full and the experience of God so intensively lived that he, in these hours of sufferance ... already sees and already touches Christ," Ruini told hundreds of faithful in Rome.

Muslims in France were praying for the pontiff because he was a "man of peace," said Dalil Boubakeur, president of the French Council of the Muslim Faith. And in New York, Rabbi James Rudin told FOX News that the Jewish community would remember this pope with fondness because of his longstanding fight against anti-Semitism.

"He constantly denounced anti-Semitism," said Rudin, religious advisor at the Center for Catholic-Jewish Studies. "He was the first pope who said Jews are our elder brothers in faith."

Rudin called John Paul's efforts to unify the Catholic and Jewish communities "historic" and spoke of the pope's own personal experience with anti-Semitism during the Holocaust in his hometown in Poland.

Washington, D.C.'s Cardinal Theodore McCarrick (search) seemed in good spirits as he made comments to reporters Friday afternoon, saying he planned to travel to Rome on Sunday.

"We're delighted at the outpouring of interest and concern in the Holy Father," he said.

Asked to comment on the future of the Catholic church in the United States, McCarrick described the recent turmoils as "a purification, but purifications are good."

"It's a chance for us to become more humble," he added.

The White House said President Bush and his wife were praying for the pope and that the world's concern was "a testimony to his greatness."

"The Pope is an inspiration to millions of Americans. He is an inspiration to people all over the world. And he has provided great moral leadership," said White House press secretary Scott McClellan.

Karol Wojtyla became a priest in 1946, just as the Iron Curtain descended across Europe, and the inspiration he provided as Pope John Paul II helped to tear it down.

"Fifty percent of the collapse of communism is his doing," Lech Walesa, founder of the Solidarity movement that toppled communism in Poland in 1989-90, told The Associated Press on Friday. Without the pope's leadership, "communism would have fallen, but much later and in a bloody way," he said.

By afternoon on Friday, a steady stream of pilgrims jammed the Via della Conciliazione, the main avenue leading to St. Peter's. Some carried candles, while others held rosaries. Some looked through binoculars or camera lenses at the window of John Paul's apartment.

Among at the square in the morning was Rome's chief rabbi, Riccardo Di Segni, who said he came "to pray here in the piazza as a sign of sharing in the grief of our brothers for their concerns and as a sign of warmth for this pope and for all that he has done."

Pope Wanted to Die at Home

Earlier Friday, the pope was reported to be celebrating Mass and receiving top aides, asking one to read him the biblical account of Christ's crucifixion and burial.

Spokesman Joaquin Navarro-Valls, at one point crying, said the pope had requested to remain in his apartment overlooking St. Peter's Square after being "informed of the gravity of his situation."

Top aides he'd received — in addition to Ruini — included the Vatican's No. 2, Secretary of State Cardinal Angelo Sodano; undersecretary of state Archbishop Leonardo Sandri; his doctrinal chief, Cardinal Joseph Ratzinger; the Vatican foreign minister, Archbishop Giovanni Lajolo; American Cardinal Edmund Szoka, the governor of Vatican City; and Archbishop Paolo Sardi, the Vatican vice chamberlain.

The chamberlain, or camerlengo, runs the Holy See between the death of a pope and the election of a new one.

The latest downturn in the pontiff's health developed after he contracted a very high fever brought on by a urinary tract infection and then experienced heart problems on Thursday.

The pope's blood pressure was plummeting on Friday, as a result of septic shock. While low blood pressure is quite serious, it is not irreversible.

The pope was being helped by his personal doctor, two intensive care doctors, a cardiologist, an ear, nose and throat specialist and two nurses.

Dr. Peter Weissberg, medical director of the British Heart Foundation, said septic shock "puts a phenomenal strain on the heart." He said between 80 percent and 90 percent of patients in this condition die within a few days.

Hospitalized twice last month following two breathing crises and with a tube placed in his throat to help him breathe, John Paul has become a picture of suffering. When he appeared at his apartment window Wednesday to bless pilgrims in St. Peter's Square, he managed to utter only a rasp.

Later that day, the Vatican announced he had been fitted with a feeding tube in his nose to help boost his nutritional intake.

The use of the feeding tube illustrates a key point of Roman Catholic policy John Paul has proclaimed: It is morally necessary to give patients food and water, no matter their condition.

As Parkinson's disease and other ailments have left him increasingly frail, the pope has been emphasizing that the chronically ill, "prisoners of their condition ... retain their human dignity in all its fullness."

The Vatican's attitude to the chronically ill has been apparent in its bitter condemnation of a judge's order two weeks ago to remove a feeding tube from Terri Schiavo, the severely brain-damaged American woman who died Thursday.

John Paul's 26-year papacy has been marked by its call to value the aged and to respect the sick, subjects the pope has turned to as he battles Parkinson's disease and crippling knee and hip ailments.

It is not clear who would be empowered to make medical decisions for an unconscious pope. The pope has no close relatives, but the Vatican has officially declined to comment whether John Paul has left written instructions.

"He will be sorely missed because [of] his teaching and his charisma ... and his example of leadership," Rudin said.

FOX News' Greg Palkot, Catherine Donaldson-Evans and The Associated Press contributed to this report.