Benedict’s remarks came on Tuesday, when he delivered a major address — which some church experts say was a defining speech of his pontificate — saying that the West, and specifically Europe, had become so beholden to reason that it had closed God out of public life, science and academia.

But the pope began this speech at Regensburg University with what he conceded were «brusque» words about Islam: He quoted a 14th Century Byzantine emperor as saying, «Show me just what Muhammad brought that was new, and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached.»

Benedict also used the word «jihad,» or holy war, saying that violence was contrary to God’s nature and to reason. But, at the end of a speech that did not otherwise mention Islam, he also said that reason could be the basis for «that genuine dialogue of cultures and religions so urgently needed today.»

After his address on Tuesday, his spokesman said the pope did not intend to insult Islam.But many experts on Islam warned that Benedict ran the risk of offense in using such strong language, with tensions between religions so high.

And today, criticism began pouring the pope’s way. The 79-year-old Benedict has taken a more skeptical, hard-nosed approach to Islam than did his predecessor, John Paul II, who died in April 2005.

«I don’t think the church should point a finger at extremist activities in other religions, Aiman Mazyek, president of the Central Council of Muslims in Germany, told the newspaper Süddeutsche Zeitung, recalling the Crusades, the Spanish Inquisition and the Vatican’s relations with Nazi Germany.

The French Council for the Muslim Religion demanded that Benedict «clarify» his remarks. «We hope that the Church will very quickly give us its opinion and clarify its position so that it does not confuse Islam, which is a revealed religion, with Islamism, which is not a religion but a political ideology,» Dalil Boubakeur, the council’s president, told Agence France-Presse.

In Kuwait, the leader of the Islamic Nation Party, Haken al-Mutairi, demanded an apology for what he called «unaccustomed and unprecedented» remarks.

«I call on all Arab and Islamic states to recall their ambassadors from the Vatican and expel those from the Vatican until the pope says he is sorry for the wrong done to the prophet and to Islam, which preaches peace, tolerance, justice and equality,» Mr. Mutairi told Agence France-Presse.

In Pakistan, Muslim leaders and scholars said that Benedict’s words widened the gap between Islam and Christianity, and risked what one official called greater «disharmony.»

«The pope’s statement is highly irresponsible,» said another ranking Muslim, Javed Ahmed Ghamidi, an Islamic scholar. «The concept of jihad is not to spread Islam with the sword.»

The criticism from Mr. Bardakoglu, the Islamic leader in Turkey, was especially strong, and carries with it particular embarrassment if Benedict is forced to cancel or delay his visit to Turkey. Many Turks are already critical of Benedict, who as Cardinal Joseph Ratzinger had in 2004 opposed Turkey’s entry into the European Union.

The official, Mr. Bardakoglu, demanded an apology, saying that the remarks «reflect the hatred in his heart — it is a statement full of enmity and grudge.»

In Morocco, the newspaper Aujourd’hui questioned whether Benedict’s call for a real dialogue between religions was made in good faith.

«Pope Benedict XVI has a strange approach to the dialogue between religions,» the paper wrote in an editorial. «He is being provocative.»