VIENNA, Austria — The U.N. nuclear monitoring agency presented documents Monday that diplomats said indicate Iran may have focused on a nuclear weapons program after 2003 — the year that a U.S. intelligence report says such work stopped.

Iran again denied ever trying to make such arms. Ali Ashgar Soltanieh, the chief Iranian delegate to the International Atomic Energy Agency, dismissed the information showcased by the body as "forgeries."

He and other diplomats, all linked to the IAEA, commented after a closed-door presentation to the agency's 35-nation board of intelligence findings from the U.S. and its allies and other information purporting to show Iranian attempts to make nuclear arms.

A summarized U.S. National Intelligence Estimate, made public late last year, also came to the conclusion that Tehran was conducting atomic weapons work. But it said the Iranians froze such work in 2003.

Asked whether board members were shown information indicating Tehran continued weapons-related activities after that time, Simon Smith, the chief British delegate to the IAEA, said: "Certainly some of the dates ... went beyond 2003."

He did not elaborate. But another diplomat at the presentation, who agreed to discuss the meeting only if not quoted by name, said some of the documentation focused on an Iranian report on nuclear activities that some experts have said could be related to weapons.

She said it was unclear whether the project was being actively worked on in 2004 or the report was a review of past activities. Still, any Iranian focus on nuclear weapons work in 2004 would at least indicate continued interest past the timeframe outlined in the U.S. intelligence estimate.

A senior diplomat who attended the IAEA meeting said that among the material shown was an Iranian video depicting mock-ups of a missile re-entry vehicle. He said IAEA Director General Oli Heinonen suggested the component — which brings missiles back from the stratosphere — was configured in a way that strongly suggests it was meant to carry a nuclear warhead.

Other documentation showed the Iranians experimenting with warheads and missile trajectories where "the height of the burst ... didn't make sense for conventional warheads," he said.

Smith and the senior diplomat both said the material shown to the board came from a variety of sources, including information gathered by the agency and intelligence provided by member nations.

"The assumption is this was not something that was being thought about or talked about, but the assumption is it was being practically worked on," Smith told reporters.

He said the IAEA presented a "fairly detailed set of illustrations and descriptions of how you would build a nuclear warhead, how you would fit it into a delivery vehicle, how you would expect it to perform."

The U.N. agency released a report last week saying that suspicions about most past Iranian nuclear activities had eased or been laid to rest. But the report also noted Iran had rejected documents linking it to missile and explosives experiments and other work connected to a possible nuclear weapons program, calling the information false and irrelevant.

The report called weaponization "the one major ... unsolved issue relevant to the nature of Iran's nuclear program."

Most of the material shown to Iran by the IAEA on alleged attempts to make nuclear arms came from Washington, though some was provided by U.S. allies, diplomats told the AP. The agency shared it with Tehran only after the nations gave their permission.

The IAEA report also confirmed that Iran continued to enrich uranium despite demands by the U.N. Security Council to suspend the work. The council has sanctions on Iran for continuing enrichment, which can produce the material needed to make atomic bombs.

Iran says its enrichment program is intended solely to produce lower-grade material for fueling nuclear reactors that would generate electricity.

Iran's ambassador to the United Nations, Mohammad Khazee, said the intelligence information turned over to the IAEA was "baseless" and alleged it was fabricated by an Iranian opposition group.

"I'm afraid to say that, according to my information, some of these allegations were produced or fabricated by a terrorist group, which are listed as a terrorist group in the United States and somewhere else in Europe," Khazee said told the AP in New York.

He appeared to be referring to the Mujahedeen Khalq, also known as the People's Mujahedeen Organization of Iran, which was listed as a foreign terrorist group by the U.S. government in 1997 and the European Union last year.

Associated Press writer Edith M. Lederer at the United Nations contributed to this report.