Evangelist Franklin Graham is scheduled to speak at the Pentagon on the National Day of Prayer.

But his invitation has riled up at least one group which is demanding a more "inclusive speaker" for the event on May 6.

Michael L. Weinstein of Military Religious Freedom Foundation is vehemently opposed to Graham speaking for the Pentagon's NDP event because of the evangelist's former comments on Islam being an "evil" religion and his ties to conservative Christian group the National Day of Prayer Task Force.

"Mr. Graham has never retracted or apologized for these statements, and, in fact, was still defending them as recently as December 2009 in an appearance on CNN," Weinstein wrote in a letter to Secretary of Defense Robert Gates this week.

Graham, son of famed evangelist Billy Graham, drew fire after the 2001 terrorist attacks when he called Islam "a very evil and wicked religion."

He has since clarified his remarks, saying he does not believe Muslims are evil people because of their faith. But he decried the evil that has been done in the name of Islam.

Last year, he told CNN's Campbell Brown, "I don't agree with the teachings of Islam. I find it to be a very violent religion."

His spokesman, Mark DeMoss, told The Associated Press that Graham hasn't changed his views on Islam.

Graham had been invited to speak at the Pentagon in 2003, which outraged the Muslim community. His invitation to speak at the Pentagon this year prompted some U.S. military personnel and DoD employees of the Muslim faith to contact the Military Religious Freedom Foundation for help, according to Weinstein.

"MRFF hereby demands ... that the Pentagon Chaplains Office immediately rescind its invitation to Mr. Graham," wrote Weinstein, a '77 graduate of the U.S. Air Force Academy.

Weinstein further blasted the Pentagon Chaplains Office for its affiliation with the National Day of Prayer Task Force, which he described as being exclusively fundamentalist Christian.

Graham is the honorary chairman for the National Day of Prayer Task Force this year.

"While the NDPTF, of course, has every right, as a private organization, to organize exclusively Christian events and to prohibit the participation of non-Christians, the Pentagon Chaplains Office absolutely cannot endorse or provide a selective benefit to this non-federal entity by shamefully, disgracefully, and unconstitutionally affiliating the Pentagon NDP event with it," Weinstein asserted.

The complaint comes days after a federal judge in Wisconsin struck down a federal statute creating the "National Day of Prayer" and ruled it as unconstitutional.

Graham denounced the ruling, saying the nation is in need of prayer now more than ever.

"To act like a National Day of Prayer is a bad thing or somehow subversive is ridiculous," he said in an earlier statement. "At a time when our country is waging two wars, approval ratings for Congress are at historic lows, unemployment is at a 70-year high and financial institutions have collapsed around us, I can’t imagine anyone seriously opposing a National Day of Prayer."

Christians have been urged to sign a petition supporting the annual prayer observance and are also asking President Obama to appeal the decision. Obama still intends to recognize the National Day of Prayer on May 6.

The National Day of Prayer is an annual observance held on the first Thursday of May, inviting people of all faiths to pray for the nation.