A Roman Catholic cardinal has suggested the Pope may abdicate because of his old age and illness.
Church leaders argue there is nothing wrong with the Pope's mind
"I am sure he has been asking himself [this] for some time," Argentina's Cardinal Jorge Mejia told a newspaper.
However, the Vatican's top legal figure, Cardinal Mario Francesco Pompedda, said on Friday that there was no question of John Paul II quitting.
A day after marking 25 years in office, the Pope continued his work, receiving the Polish president.
Speaking to reporters afterwards, Aleksander Kwasniewski said he had found his compatriot "in good shape" but added that he was suffering from "very serious ailments".
During Thursday's open-air jubilee Mass at the Vatican, the Pope asked people to pray for God to give him the strength to continue his work.
ABDICATING ST PETER'S THRONE
Provision does exist and has been used previously, usually for political or moral reasons
Last Pope to resign was Gregory XII in 1415
Pope who crowned Napoleon I emperor in 1804, Pius VII, left an abdication note in Rome in case he should be imprisoned in France
source: Catholic Encyclopaedia
But although he looked alert, the 83-year-old was slumped in his chair and his words were often slurred and barely comprehensible. Part of his homily was read by an aide.
"Someone who cannot speak cannot celebrate a mass," Cardinal Mejia told Argentina's respected La Nacion newspaper in its Thursday edition.
Seeking to quash speculation, Cardinal Pompedda, the head of the Supreme Tribunal of the Apostolic Signature - the Church's official court, insisted that the Pope was still able to perform his duties.
"These days the Pope is clearly having difficulty speaking which is purely phonetic but he has no impediment in expressing his thoughts," he said.
"Therefore, the question of 'resigning' the pontificate is not a topic of discussion."
President Kwasniewski appealed to people to stop putting pressure on the ailing pontiff by asking for further papal visits.
"These repeated invitations hurt him," he said.
"We must be understanding and not demand more from this man than he can, with very great effort, give."