"It is unacceptable for Iranian President Ahmadinejad, who refuses to renounce and end his own country's support of terrorism, to visit the site of the deadliest terrorist attack on American soil in our nation's history," said Sen. Hillary Rodham Clinton.

Former Mayor Rudy Giuliani called the idea "outrageous."

"This is a man who has made threats against America and Israel, is harboring [Osama] Bin Laden's son and other al Qaeda leaders, is shipping arms to Iraqi insurgents and is pursuing the development of nuclear weapons," he said.

White House spokesman Gordon Johndroe said an Ahmadinejad visit to the World Trade Center site "is a matter for the City of New York, but it seems more than odd that the president of a country that is a state sponsor of terror would visit Ground Zero."