Iran needs the ability to produce nuclear fuel because it cannot rely on other nations to supply enriched uranium to the Islamic regime's planned reactors, the Iranian president said Thursday.

Mahmoud Ahmadinejad — speaking to a gathering of selected journalists — also contended that Washington does not have the will to launch a military strike on Iran over its nuclear ambitions, which Tehran insists is for peaceful energy production but the West fears is a clandestine effort to gain atomic weapons.

"We're not concerned at all that a confrontation will occur," said Ahmadinejad, who is in New York for the U.N. General Assembly. "What (factors) demand a war?"

Ahmadinejad has used the U.N. session to host a variety of gatherings — including students and religious leaders — to press Iran's claims that it does not seek nuclear arms and has the right to develop reactors as an energy alternative to its vast oil and gas reserves.

Ahmadinejad also has taken broad swipes at the United States and Israel — saying the American "empire" is collapsing, branding the Jewish State as a "cesspool" that will someday disappear and again questioning the extent of the Holocaust.

Protesters, including Jewish groups, have gathered outside the U.N. building and Israeli President Shimon Peres called Ahmadinejad's U.N. address "a repetition of the darkest accusations in the name of Hitler."

But the nuclear standoff has loomed largest.

Ahmadinejad said Iran must develop its own centrifuge system to enrich uranium or risk being held hostage to international supplies that could be halted. Western powers have offered Iran economic incentives to abandon its enrichment program and take outside supplies of fuel — suitable for reactors but not concentrated enough for weapons.

Ahmadinejad, however, said Iran would not step back from its own enrichment projects.

"What guarantee do we have that they would give (the nuclear fuel) to us?" he told the media gathering, which included The Associated Press.

He cited past contracts with U.S. and European companies for power plants and other projects that were canceled after the 1979 Islamic Revolution.

"Iran paid billions (and) Western countries pulled out ... Who do we take our complaints to?" he said.

Iran, however, has turned to Russia to build its first nuclear plant at Bushehr near Iran's Persian Gulf coast. Earlier this week, Russia blocked talks on imposing new sanctions on Iran.

Iranian officials have said the Bushehr plant could begin some operations later this year.

In Vienna, Austria, the International Atomic Energy Agency's 35-member board is holding meetings this week that include internal reports on Iran's nuclear capabilities — with one study citing a significant increase in Iran's uranium-enrichment centrifuges.

A statement by the European Union said Iran's demands on its own enrichment program "brings us closer to the moment where Iran will have fissile materials for a weapon."

But Ahmadinejad answered back from New York — reiterating his claim that nuclear weapons are no long a factor in the global balance of power following the end of the Cold War.

"The time for the atomic bomb has come to an end. If the atomic bomb could do any good, it would have kept the Soviet Union from collapsing," he said. "Those who stockpile or build the atomic bomb are backward thinking."

Ahmadinejad also looked ahead to Iran's presidential election next year, when he is expected to face challengers that could include the current Tehran mayor — Ahmadinejad's former post — and parliament speaker Ali Larijani, who previously served as Iran's top nuclear negotiator.

Ahmadinejad said he encouraged Larijani's possible bid to run for president.