John Paul pressed a hand to his face and pounded a lectern in apparent frustration during his Palm Sunday appearance, which lasted less than a minute, at a window of his apartment overlooking St. Peter's Square.
It was the first time in 26 years as pope that he was unable to preside over the Mass ushering in Holy Week, the most important season on the Christian calendar and long one of his favorite appointments.
The pope did not utter even a brief blessing, perhaps indication that John Paul II may not be recovering as well as the Vatican would have the faithful believe, reports CBS News Correspondent Allen Pizzey.
His face looked drawn and his lips curled in a pucker.
Just a week earlier, before his release from a Rome hospital after Feb. 24 surgery to insert a breathing tube in his windpipe, the 84-year-old John Paul had managed two sentences in a raspy voice. But on Sunday, with up to 50,000 expectant pilgrims packing the square, he said nothing, slapping the lectern with an open hand after waving an olive branch.
An aide then hastily closed the white curtains to his window. Vatican television did not zoom in close on the pope as it has during his other recent window appearances.
The adoring crowd applauded and grew teary-eyed at the sight of John Paul, clearly moved even though he didn't address the faithful or read out a few lines of his weekly blessing.
"You could feel his presence in the whole square, even if he didn't speak," said Pauline Everden, an Anglican tourist from England.
But the mute appearance threw fresh doubts on the pope's convalescence after being hospitalized for two breathing crises in less than a month. It was yet another signal that the papacy is entering a new phase, with the pope in the background delegating important events to top churchmen.
The use of television and video has become more important to John Paul's papacy as he is slowed by his ailments, and the Vatican seeks to reassure the faithful with his image. Pilgrims at St. Peter's on Sunday strained to see him high in his window and followed his appearance on giant video screens erected in the square.
John Paul's vicar for Rome, Cardinal Camillo Ruini of Italy, presided over the Palm Sunday Mass, and Archbishop Leonardo Sandri of Argentina — the pope's voice for the public since his latest hospitalizations — read out a message from the pontiff to the crowd gathered on the sun-drenched square.
"With great joy I salute you," the pope's message said.
He singled out young people for a special greeting and mentioned World Youth Day in Cologne, Germany, in mid-August — his only scheduled foreign trip this year. But he did not express his desire to be there, something he has done on several recent occasions.
The pope suffers from Parkinson's disease, which affects muscle control and makes it difficult for him to speak clearly. The Vatican has said the pope's doctors will decide when the tube should be removed from his throat.
Sunday's Mass, which commemorated Jesus Christ's triumphant entry into Jerusalem, included a special prayer for the pontiff, calling him "our beloved father" and asking that he continue in his "service up to the gift of life."
In his homily, Ruini spoke of Christ's ordeal and the "drama and mystery" of suffering and its meaning for humanity. The Italian cardinal said Christ's cross brings "new energies" and "shines with special clarity on the weary face of the Holy Father."
Sunday kicked off a busy week of events culminating in a week with Easter Sunday. The only Easter week ceremony not penciled in for someone else to do is the Procession of the Cross on Good Friday, which has led to the rumor that the Pope will appear there, either as a spectator or on a video link, reports Pizzey.