Pressure mounted on Pope Benedict to issue a personal apology on Sunday when he makes his first public appearance since his comments about Islam sparked Muslim fury across the world.
The Vatican said on Saturday the Pope was sorry Muslims had been offended and that his comments had been misconstrued, but Muslim countries and religious groups remained angry at what they said portrayed Islam as a religion tainted with violence.
Morocco withdrew its ambassador to the Vatican, calling the Pope's remarks "offensive", while Egypt's Muslim Brotherhood -- the main opposition force in the country's parliament -- said the statement issued by the Vatican was not enough.
"We feel he has committed a grave error against us and that this mistake will only be removed through a personal apology," said the Brotherhood's deputy leader Mohammed Habib.
The Pope, leader of the world's 1.1 billion Roman Catholics, was due to give his regular Sunday blessing -- known as the Angelus -- in St. Peter's Square, an occasion often used by pontiffs to express the church's views on current affairs.
Muslim anger erupted when the Pope made a speech in Germany on Tuesday referring to criticism of the Prophet Mohammad by 14th century Byzantine Emperor Manuel II Palaeologus, who said everything Mohammad brought was evil "such as his command to spread by the sword the faith he preached".
Using the terms "jihad" and "holy war", the 79-year-old Pope said violence was "incompatible with the nature of God".
But the Vatican's Secretary of State, Cardinal Tarcisio Bertone, said in a statement the Pope "had absolutely no intention" of presenting Emperor Manuel's opinions on Islam as his own.
"The Holy Father thus sincerely regrets that certain passages of his address could have sounded offensive to the sensitivities of the Muslim faithful," Bertone said in a statement, only a day after taking over as "deputy pope".
He said the Pope, elected 17 months ago, confirmed "his respect and esteem for those who profess Islam" and hoped his words would be understood in their "correct meaning".
The academic speech was meant as a "a clear and radical rejection of the religious motivation for violence, from whatever side it may come," said Bertone.
The backlash over the Pope's comments has cast doubt on his planned visit to Turkey in November.
Prime Minister Tayyip Erdogan, a pious Muslim with roots in political Islam, said before the Vatican statement the Pope's comments were "ugly and unfortunate" and should be withdrawn.
Yemen's president publicly denounced the pontiff and five churches -- only one of them Catholic -- were attacked in the West Bank, although no one was hurt.
Egypt's Foreign Ministry summoned the Vatican's envoy to Cairo to express "extreme regret" at Benedict's speech.
But Chancellor Angela Merkel and other German politicians defended his comments, saying he had been misunderstood.
"It was an invitation to dialogue between religions," Merkel told the mass circulation Bild newspaper in an interview.
Vatican insiders and diplomats say the Pope may have mixed up his new role with his former posts as a theologian and head of the Congregation for the Doctrine of the Faith, when as Cardinal Joseph Ratzinger he was known as a disciplinarian.
Angry Muslim leaders flung what they saw as allegations of violence back at the West.
"How can (the Pope) imply that Muslims are the creators of terrorism in the world while it is the followers of Christianity who have been aggressive against every country of the Islamic world?" prominent Saudi cleric Salman al-Odeh said. "Who attacked Afghanistan and who invaded Iraq?"