As Iranian President Mahmoud Ahmadinejad addressed the United Nations General Assembly Wednesday, crowds of Iranian-American activists and their supporters gathered outside the complex for a "pro-democracy" rally to voice their opposition.

The demonstrators waved signs and a large banner covered in photographs reading "Fallen For Freedom In Iran." They stomped on pictures of Ahmadinejad, saying he should not appear at the UN as the legitimate leader of the Iranian people.

Ahmadinejad, who will be forced to step down as president of Iran next year because of term limits, called in his UN speech for a new world order to emerge from what he calls American "bullying" and domination.

"Unilateralism, application of double standards, an inquisition of wars, instability and occupation to ensure economic interests and expand dominance over sensitive centers of the world have turned to be the order of the day," Ahmadinejad said through an interpreter.

Iranian dissidents and U.S. officials are concerned that the current regime in Iran is trying to build a nuclear weapon.

In a recent "60 Minutes" interview, Ahmadinejad downplayed Iran's nuclear ambitions, but many demonstrators at the rally said the Obama administration needs to take a harder line against Iran.

"We are here to tell everybody that he is not the president of the Iranian people and we are against his presence at the UN. And we want to just give our voice here and let the people know about it," said one protester.

"I wanna tell him that he's not welcome here because he's just killer, he's terrorist," said another protester.

Prominent U.S. politicians present at Wednesday's rally said a regime change in Iran will bring about positive changes.

"Now we are going to watch Iran change into a nuclear power while the President of the United States sits by and uses all these weasel words like 'all options are on the table,'" said former Mayor Rudolph Giuliani. "We are not going to be for containment."

"We can't stop somebody from coming here to speak as part of the United Nations, or it violates our terms of understanding," said former House Speaker and former Republican presidential candidate Newt Gingrich. "But I do think our position ought to be that we will to as rapidly as possible replace him and then the people who are here today, the dissidents, would be the government."

Former Democratic New Mexico Governor Bill Richardson, who also served as U.S. Ambassador to the United Nations, said that he believes the president "has said he is not going to tolerate a nuclear Iran."

"They're not there yet," Richardson said. "I think we've got to continue sanctions, diplomacy but another viable alternative is to create and help an opposition for him."

Critics also say it is offensive to have Ahmadinejad speak on Yom Kippur because he has called for the destruction of Israel and has repeatedly denied the Holocaust.

However, the UN does not have religious holidays.

Both U.S and Israeli officials have said they cannot take a chance with Iran and will continue to monitor the country's every move.