A large number of the victims of suicide attacks in Saudi Arabia, Turkey, Iraq, and elsewhere have been Muslims.
Sheik, who is respected in the Arab world as the foremost cleric in the country considered the birthplace of Islam, spoke at Namira Mosque, a televised sermon watched by millions of Muslims in Saudi Arabia and other Gulf states.
The mosque is close to Mount Arafat, where the pilgrims converged yesterday for the climax of their annual trek. This year's hajj has been carried out amid heightened security after a year of terror attacks in the kingdom.
In speaking of terrorists who killed fellow Muslims, Sheik was clearly referring to the Prophet Muhammad's final sermon, delivered on Mount Arafat 14 centuries ago.
It contained the line: "Know that every Muslim is a Muslim's brother, and the Muslims are brethren. Fighting between them should be avoided."
Sheik also criticized the international community, accusing it of attacking Wahhabism, the sect whose strict interpretation of Islam is followed in Saudi Arabia.
"This country is based on this religion and will remain steadfast on it," he said.
"Islam forbids all forms of injustice, killing without just cause, treachery, . . . hijacking of planes, boats, and transportation means," he said.The Saudi government conducted a crackdown on extremist groups after suicide bombers attacked housing compounds inhabited by foreigners last May. Saudi and US officials blamed the attack, and a similar suicide bombing in November, on groups linked to Al Qaida, which is led by the Saudi-born Osama bin Laden.