Catholics in St. Peter's Square and around the world are praying for Pope John Paul II as he clings to life in his papal apartment.
The pontiff suffered heart failure on Thursday during treatment for a urinary tract infection. His condition deteriorated further overnight.
The Vatican says his kidneys are not functioning properly and his breathing is shallow.
Cardinal Edmund Szoka, Vatican spokesperson, says, "His breathing was very difficult, very labored."
The Vatican acknowledged the gravity of the Pope's condition Friday morning, but said the pontiff was able to participate in a mass and listen to Scripture about the crucifixion and burial of Jesus.
"Despite his failing health, the Pope himself decided not to return to the hospital. Instead, he has chosen apparently to live out his final moments in his apartment overlooking St. Peter's Square.
Outside, thousands have gathered to recite the Rosary and wait for word. The Sacrament for the Sick and Dying was administered to the Pope Thursday, and the Vatican says he has taken the Holy Communion reserved for those close to death.