The UN atomic agency plans to reveal intelligence next week suggesting Iran made computer models of a nuclear warhead and other previously undisclosed details on alleged secret work by Tehran on nuclear arms, diplomats told The Associated Press on Friday.

Other new confidential information the International Atomic Energy Agency plans to share with its 35 board members will include satellite imagery of what the IAEA believes is a large steel container used for nuclear arms-related high explosives tests, the diplomats said.

The agency has previously listed activities it says indicate possible secret nuclear weapons work by Iran, which has been under IAEA perusal for nearly a decade over suspicions that it might be interested in develop such arms.

Open gallery view International Atomic Energy Agency logo Credit: AP

But the newest compilation of suspected weapons-related work is significant in substance and scope. The diplomats say they will reveal suspicions that have not been previously made public and greatly expand on alleged weapons-related experiments that have been published in previous reports on Iran's nuclear activities.

It also comes as the drumbeat of reports about possible military action against Iran's nuclear facilities intensifies.

Israeli President Shimon Peres said Friday that the international community is closer to pursuing a military solution to the standoff over Iran's nuclear program than a diplomatic one. The comments, from a known dove, assumed added significance because they followed unsubstantiated reports that Prime Minister Benjamin Netanyahu was seeking his government's support for a strike against Tehran.

British media have separately cited unnamed British officials as saying London was prepared to offer military support to any U.S. strike on Iran's nuclear facilities.

In Vienna, the diplomats - from IAEA member nations - asked for anonymity because their information was privileged. One of them said the material drawn up by IAEA chief Yukiya Amano will be in an annex running around 12 pages and attached to the latest of a regular series of agency reports on Iran's nuclear enrichment program and other activities that could be used to arm nuclear missiles.

Previously undisclosed information contained in the annex, said the diplomats, will include:

- Intelligence from unnamed member states that a bus-sized steel container, located at the Iranian military base of Parchin is likely being used for nuclear-related high explosives testing of the kind needed to release an atomic blast. The agency has satellite imagery of the container.

- Expanded evidence that Iranian engineers worked on computer models of nuclear payloads for missiles.

Significantly, said the diplomats, these alleged experiments took place after 2003 the year that Iran was believed to have stopped secret work on nuclear weapons, according to a 2007 U.S. intelligence assessment. But diplomats have told the AP that Tehran continued arms-related experiments in a less concentrated way after that date, a view reflected by recent IAEA reports that have detailed suspicions that such work may be continuing up to the present.

The annex will also say that more than 10 nations have supplied intelligence suggesting Iran is secretly developing components of a nuclear arms program - among them an implosion-type warhead that it wants to mount on a ballistic missile.

It says that two foreign "sources" - apparently countries or nongovernment groups within countries - have helped Iran develop a weapons design, without naming them. And it details how Iran bought "dual use" - peaceful or military - nuclear technology from the black market network of renegade Pakistani scientist A. Q. Khan, as well as alleged preparations for a nuclear weapons test.

The upcoming report is meant to ratchet up pressure on the Islamic republic to stop four years of stonewalling of IAEA experts seeking to follow up intelligence of such secret weapons-related experiments.

Iran denies such activities, asserting that they are based on intelligence fabricated by Washington. It also denies that its uranium enrichment program - under UN Security Council sanctions because it could manufacture fissile warhead material - is meant for anything else but making nuclear fuel.

In his previous report in September, Amano said he was "increasingly concerned" about a stream of intelligence suggesting that Iran continues to work secretly on developing a nuclear payload for a missile and other components of a nuclear weapons program.

He said "many member states" are providing evidence for that assessment, describing the information the agency is receiving as credible, "extensive and comprehensive."

That report warned of the "possible existence in Iran of past or current undisclosed nuclear related activities" linked to weapons work. In particular, said the report, the agency continues to receive new information about "activities related to the development of a nuclear payload for a missile."

Acquired from "many" member states, the information possessed by the IAEA is "extensive and comprehensive ... (and) broadly consistent and credible," said the report.

The U.S. and its Western allies on the Security Council hope the upcoming report will be strong enough to persuade the IAEA board at its mid-November meeting to report it anew to the council. It was the board that first referred Iran to the Security Council in 2006 - a move that led to a series of sanctions punishing Tehran for its nuclear defiance.

If that fails, they would like a board resolution setting a deadline of only a few months for Iran to start cooperating with the agency's probe - or face the prospect of renewed Security Council referral at the next board meeting in March.

One of the diplomats said that Iran was given a copy of the annex earlier this week, giving a chance for comment that would be included when the report is shared with board members. Iran initially refused to accept a copy of the report, he said, reflecting its rejection of the allegations.

A call requesting comment left on the cell phone of Ali Asghar Soltanieh, Iran's chief delegate to the IAEA, was not immediately returned.