Religious and political leaders stepped up efforts to defuse the growing tensions between Muslims and Christians, as demonstrations continued across the Islamic world against the cartoons of Muhammad.

Pope Benedict XVI announced a three-day visit in November to Turkey, where the murder of a Catholic priest has been linked to the outrage caused by the Danish cartoons.

Father Andrea Santoro, 60, was shot in the back on Sunday as he knelt to pray in Trabazon in eastern Turkey.

His suspected killer, a teenage boy, is reported to have told police he was incensed by the cartoons, and L’Osservatore Romano, the Vatican newspaper, said the killing was clearly related to the caricatures, saying it "fits into the climate of tension in recent days."

Javier Solana, the EU’s Foreign Policy Chief, said he would travel next week to Saudi Arabia, Egypt, Jordan, the Palestinian territories and Israel to "see if we can recuperate after this affair of the cartoons."

However, he gave warning that governments should not allow demonstrations to get out of control. "It is very important that Arab countries do not break the rules on international law and conventions on respecting diplomatic premises and people," he said.

His warning came after several European embassies were destroyed in the Middle East, and Washington accused the Syrian and Iranian governments of stoking up demonstrations to bolster public support. The protests continued today from South Africa to Bangladesh, with violent clashes in Afghanistan and Pakistan.

European leaders that have defended the printing of the cartoons in the name of freedom of speech faced accusations of hypocrisy today.

An author was put on trial in Germany for denying the Holocaust, and Catholics in Poland expressed outrage after a music magazine published a picture of an icon of the Virgin May with the face of the pop singer Madonna transposed on to it.

Ernst Zuendel, 66, who has been in prison since being deported from Canada last year, faces charges of inciting racial hatred and denying the Nazis killed six million Jews.

Claiming the Holocaust did not happen is a crime in Germany, Austria and several other European countries. Muslim leaders in Iran and elsewhere have repeatedly accused the West of double standards for preaching freedom of speech as an excuse to denigrate their prophet while imprisoning people for questioning the Holocaust.

The Iranian regime has said that it does not believe the Holocaust happened and an Iranian newspaper is holding a contest for Holocaust cartoons.

In Poland monks expressed their shock at the decision of a music magazine to have a cover showing the tampered picture of the much revered icon of the Black Madonna, which some Poles believe was painted by St Luke the evangelist.

"We are shocked to see, yet again, the miraculous icon of the mother of God used in a profanatory way for advertising and business purposes," Paulinian monks at Jasna Gora monastery in the southern city of Czestochowa, who are custodians of the icon, said in a statement.

They gave warning: "Current events have shown us where abuse of religious images and symbols can lead", although they did not threaten any violence.

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