NEW YORK -- The Council of Mosques of the United States has become the first Islamic group to join Religion in American Life, an organization that uses advertising agencies to promote the role of faith in society.

Dawud Assad, president of the organization of 195 mosques, said the Muslims "look forward to some good cooperation in the future" with "our brothers and sisters."

"We're at a new stage at which we cease to be a religion on the margins, but a religion of American people related to American life," said Gutbi E. Ahmed, director of the Muslim World League. "We're now ready to interact with the rest of American people, particularly in relation to its religious communities."

Leaders of Protestant, Roman Catholic, Eastern Orthodox and Jewish faiths welcomed the Muslim entry into the organization, which works to encourage regular worship and community service.

"This is an historic moment for RIAL and, I dare say, for America," said Rabbi Joseph B. Glaser, chairman of the group and executive vice president of the Central Conference of American Rabbis.

"We have broken a major barrier," Glaser said.

"When Religion in American Life was first formed in the 1940s, it was a Protestant organization," Glaser said. "Later they took in the Catholics and it became a Christian organization. Then they took in the Jews and it became a religious organization. Now, with the entry of Islam, we become a holy organization."

In April, when RIAL announced its new "Invite a Friend" multimedia campaign, the question was raised whether Islamic groups had been invited to participate. The Rev. Nicholas B. van Dyck, the Presbyterian minister who is president of the organization, said then that although conversations were "in process," some questions had been raised in the Muslim community about the taking part in a joint effort with Christian and Jewish congregations.

Muslims previously have been involved in interfaith theological dialogues, but not in interreligious activity on a national basis.

"We had not been willing to join before because we would be drowned," Assad said. But, he said, Muslims now have organizational maturity and strength to facilitate interreligious cooperation.

In addition to the mosques, the council Assad heads includes worshipping centers in most major cities. He said there also are now more than 1,000 Muslim community organizations, some worshipping in basements or other makeshift places.

Assad noted that the Koran and mainstream Islamic teaching mandates that Muslims enter dialogue with Jews and Christians, the other "people of the book."

"Our problem in this country is that we hear so much about the radical fringes of Islam," van Dyck said in an interview. "Once we got into serious discussions with the Council of Mosques, we found that our ancient fears were unfounded."

RIAL and the Advertising Council, with which it is working, hope to be able to design ads that can be used by Muslim groups by next spring as part of the "Invite a Friend" campaign, van Dyck said.

Assad said he didn't anticipate that the council's participation would notably increase the number of Muslims worshipping in mosques, since "usually these people already know about the place of worship {in their neighborhood}, and they participate." He said, however, that Muslims visiting from overseas might benefit from the fact that mosques will now be listed along with churches and synagogues in the worship directories that RIAL sponsors in hotels in various cities.

According to RIAL, members of its participating religious bodies account for 84 percent of the religiously affiliated people in the United States.