Following deadly bombings in Britain and other nations, American Muslim scholars issued an edict Thursday condemning religious extremism and calling terrorists "criminals, not 'martyrs.' "

The 18-member Fiqh Council of North America said Muslims were barred from helping "any individual or group that is involved in any act of terrorism or violence."

"There is no justification in Islam for extremism or terrorism," the scholars wrote in the edict, called a fatwa. "Targeting civilians' life and property through suicide bombings or any other method of attack is haram — or forbidden."

Many Muslim leaders overseas have made similar statements in recent weeks, but some have left an opening for violence to be used in certain situations. One group of British Muslim leaders who denounced the July 7 attacks in London said suicide bombings could still be justified against an occupying power — drawing criticism that it invited violence in Iraq, where civilians along with coalition troops have been killed.

However, the U.S. scholars said in a Washington news conference that their prohibition applied to attacks on civilians everywhere. Their fatwa states that Muslims are obligated to help law enforcement authorities "protect the lives of all civilians."

"Suicide bombing is forbidden in Islam," said Muzammil H. Siddiqi, head of the Fiqh Council. "This is not the solution, it is not the right way of doing things. Occupation is wrong, of course, but at the same time this is not the way."

Islam has no central authority and the council serves an advisory role for American Muslims, who could number as high as 6 million. But some question whether the panel's statements would sway extremists.

While the Muslim world does not look to America as a center of Islamic thinking, U.S. Muslims wanted to send a message about their faith. Muslim leaders lament that their repeated condemnations of terrorism since the Sept. 11, 2001, attacks have been ignored by critics.

The Muslim Public Affairs Council, an advocacy group based in Los Angeles, started the "National Anti-Terrorism Campaign," urging Muslims to monitor their own communities, speak out more boldly against violence and work with law enforcement officials.

The Council on American-Islamic Relations is running a TV ad and a petition-drive called "Not in the Name of Islam," which repudiates terrorism. In New York and other cities, mosque leaders have joined advisory committees created by the FBI to build relations between law enforcement and their local communities.