FMEP President Philip Wilcox told FoxNews.com he's no longer sure Hassoun plans to attend, and added that the invitation might be rescinded.

"I was not aware of the deplorable statement [Hassoun made] about suicide bombing," Wilcox said. "We often have people who are controversial and provocative, and this mufti has in the past made what appear to be very positive comments about the relationships between Jews, Muslims and Christians.

"But I can't discount what he said in his speech about suicide bombing in the U.S. and Europe," Wilcox said. "We are still considering the invitation, so stay tuned."

Wilcox's group's website says it is "dedicated to promoting, through various activities, a just solution to the Israeli-Palestinian conflict that brings peace and security to both peoples."