Terry Jones expressed sympathy on Tuesday for families of the victims of the 2001 terrorist attacks. He also spoke out against the radical Islam he said was the cause of their deaths.
Jones says he doesn't know whether those planning the mosque and Islamic cultural centre are radicals.
He says he hopes they choose not to build the mosque there, just as he decided not to burn the Islamic holy book.
Jones says he has nothing against peaceful Muslims.
Some of Jones' supporters identified themselves as Coptic Christians from Egypt, saying they had fled persecution because of their religion.