Pope Benedict has cancelled this week's planned visit to Rome's oldest university following protests over his alleged hostility to scientists' freedom of research.
The 80-year-old pontiff had been scheduled to attend Thursday's opening of the academic year at the La Sapienza university and to give an address.
''In the wake of the events of the last few days, it was considered opportune to put off the event,'' said a brief statement issued by the Vatican press office.
Pointing out that the pope was invited to the ceremony by the university's dean, the statement said Benedict would in any case send the speech he had prepared for the event.
Vatican sources said the decision not to go to La Sapienza was taken in order to avoid the possibility of people being injured in scuffles. Other sources said Vatican authorities were keen to avoid TV pictures of anti-pope initiatives being beamed around the globe.
News of the pope's decision drew cheers from students who had been planning to stage a demo during the pope's visit. The dean of La Sapienza had just given them permission to hold the rally in the university grounds.
Lecturers who signed a letter urging the university to cancel the visit also expressed their satisfaction.
In their letter, physics professors highlighted Benedict's defence, when he was still Cardinal Joseph Ratzinger, of the Catholic Church's trial of great Italian astronomer Galileo Galilei.
Galileo, who went against contemporary thinking by saying the earth revolved around the sun, was found guilty of heresy in 1633. He was forced to renounce his scientific findings publicly.
Speaking in Parma in 1990, Benedict said the trial was ''reasonable and just''.
''These words offend and humiliate us,'' said the professors in their letter, going on to describe the papal visit as ''incongruous''.
Separately, groups of students also opposed to the visit organised protests, staging a sit-in at the university's main administrative building and putting up anti-pope banners.
All Italian politicians expressed deep regret over the pope's decision to stay in the Vatican on Thursday.
Premier Romano Prodi condemned the campaign to stop the papal visit and expressed his ''solidarity'' with Benedict, urging the pope to reconsider the decision and ''keep the original programme''.
''No voice must be silenced in this country, certainly not the pope's,'' added the premier, who is a practising Catholic.
''I'm very sorry about this, sincerely sorry,'' said the left-wing Minister for Universities Fabio Mussi. ''You don't have to agree with what he says, but the right to speak shouldn't be denied to anyone''.
Education Minister Giuseppe Fioroni said the events showed a need to ''eliminate intolerance and cultural shortsightedness''.
The centre-right opposition was uniformly outraged that the pope should have been kept away, blaming leftists among students and staff for what it called a ''blow to democracy''.
Pier Ferdinando Casini, chairman of the Catholic-oriented UDC party, attacked the professors who had written the letter of protest which sparked the furore.
''Congratulations to the 67 people who signed it!. With their intolerance they have shown the desolate state of Italian universities,'' he said. ''If these are our children's teachers, we should be afraid for our future''.
