Pope Benedict XVI said Sunday that he was "deeply sorry" about the angry reaction to his recent remarks about Islam, which he said came from a text that did not reflect his personal opinion.
Despite the statement, protests and violence persisted across the Muslim world, with churches set ablaze in the West Bank and a hard-line Iranian cleric saying the pope was united with President Bush to "repeat the Crusades."
An Italian nun also was gunned down in a Somali hospital where she worked, and the Vatican expressed concern that the attack was related to the outrage over the pope's remarks.
Benedict sparked the controversy when, in a speech Tuesday to university professors during a pilgrimage to his native Germany, he cited the words of a Byzantine emperor who characterized some of the teachings of the Prophet Muhammad, Islam's founder, as "evil and inhuman."
On Sunday, he stressed the words "were in fact a quotation from a medieval text which do not in any way express my personal thought."
"At this time I wish also to add that I am deeply sorry for the reactions in some countries to a few passages of my address at the University of Regensburg, which were considered offensive to the sensibility of Muslims," the pope told pilgrims at his summer palace outside Rome.
Security was higher than usual at the palace, with police patting down many pilgrims and confiscating umbrellas with metal tips and bottles of liquids. Sharpshooters kept watch from a balcony and other officers, dressed like tourists, monitored the crowd with video cameras.
Police headquarters across Italy also were ordered to raise security at potential Catholic targets. At the Vatican, though, no additional security measures could be seen as tourists strolled across St. Peter's Square.
Muslim leaders in the Mideast gave mixed reactions to the pontiff's statement Sunday.
The leader of Egypt's largest Islamic political group, the Muslim Brotherhood, said that "while anger over the pope's remarks is necessary, it shouldn't last for long."
"While he is the head of the Catholic Church in the world, many Europeans are not following (the church) so what he said won't influence them. Our relations with Christians should remain good, civilized and cooperative," Mohammed Mahdi Akef told The Associated Press.
However, the former deputy of Cairo's Al-Azhar Mosque, the Sunni Arab world's most powerful institution, told Al-Arabiya TV the explanation was "not enough."
"He should apologize because he insulted the beliefs of Islam. He must apologize in a frank way and say he made a mistake," Mahmoud Ashour said.
Mohammed al-Nujeimi, a professor at the Institute of Judicial and Islamic Studies in Riyadh, Saudi Arabia, also criticized the pope's statement.
"The pope does not want to apologize. He is evading apology and what he said today is a repetition of his previous statement," he told Al-Arabiya TV.
The Vatican had released a statement Saturday saying the pope "sincerely regrets" that Muslims were offended, but stopped short of apologizing.
In his speech on Tuesday, Benedict quoted from a book recounting a conversation between 14th century Byzantine Christian Emperor Manuel Paleologos II and an educated Persian on the truths of Christianity and Islam.
"The emperor comes to speak about the issue of jihad, holy war," the pope said. "He said, I quote, '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."'
The remarks continued to spark protests and violence across the Muslim world on Sunday.
The Italian nun, who was not immediately identified, was shot in the back at S.O.S. Hospital in the Somali capital of Mogadishu by two gunmen, said Mohamed Yusuf, a doctor at the facility. The nun's bodyguard and a hospital worker were also killed, doctors said.
Nobody claimed of responsibility for the attack. The Vatican's spokesman indicated the shooting could be related to the uproar over the pope's remarks.
"Let's hope that it will be an isolated fact," the Rev. Federico Lombardi was quoted as saying by the Italian news agency ANSA. The Vatican is "following with concern the consequences of this wave of hate, hoping that it does not lead to grave consequences for the church in the world."
In the West Bank, two churches were set on fire. One attack destroyed the interior of a 170-year-old church in the town of Tulkarem; the other partially burned a church in Tubas, Christian officials said. Neither church is Catholic.
Palestinian Muslims hurled firebombs and opened fire at five churches in the West Bank and Gaza Strip Saturday, sparking concerns of a rift between Palestinian Muslims and Christians.
Hundreds of Iranians also demonstrated against the pope in cities across Iran. In Qom, the religious capital of Iran's 70 million Shiite Muslims, hardline cleric Ahmad Khatami said the pope and Bush were "united in order to repeat the Crusades."
Elsewhere, the pope's statement Sunday appeared to be easing tensions.
Turkey's foreign minister said the pope was still expected to visit in November in what would be his first trip to a Muslim nation. "From our point of view, there is no change," Abdullah Gul told reporters before departing for a trip to the United States.
Turkish Prime Minister Recep Tayyip Erdogan had cast doubt on the trip Saturday amid angry reactions from many leaders in Turkey's staunchly secular government.
However, some in Turkey rejected the pope's explanation on Sunday. State Minister Mehmet Aydin said he seemed to be saying he was sorry for the outrage but not the remarks themselves.
"You either have to say this 'I'm sorry' in a proper way or not say it at all," he told reporters in Istanbul. "Are you sorry for saying such a thing or because of its consequences?"