Muslim prelates and scholars have strongly condemned as "anti-Islamic" Tuesday's assault on the World Trade Centre in New York City and the Pentagon in Washington.
Sheikh Muhammad Said Tantawi, rector of the 1,000-year-old Islamic University of al-Azhar in Cairo, who is regarded by orthodox Sunni Muslims as the leading source of Islamic opinion, castigated those who mounted the attacks.
Although he previously ruled that "one who blows himself up amongst enemies in order to defend his land is considered a martyr", he made a distinction between self-sacrifice and random terrorism.
He said it is prohibited to kill innocent civilians and children.
His line was echoed by leading clerics in Saudi Arabia and the Gulf emirates, by the Palestinian Mufti of Jerusalem, Sheikh Ikrima Sabri, and Sheikh Ahmad Yassin, founder of the Palestinian Hamas movement.
Sheikh Muhammad Fadlallah, the spiritual mentor of the Lebanese Hizbollah, a heterodox Shia movement, repeatedly denounced the operation, blamed on Islamist militants.
He deplored the loss of civilian life. "No religion justifies such an action. It is not permissible to use innocent and peaceful civilians as a card to change a specific policy.
"While many Muslims and Islamists oppose American's pro-Zionist policy, we want to be friends with the American people."
This line was echoed by the President of Lebanon's Higher Shi'ite Council, Sheikh Abdel-Amir Qabalan, who said: "Islam is a religion of justice and equality, and it condemns any attack on civilians and the innocent."
