An Iranian exile group accused Tehran on Tuesday of pursuing efforts to develop nuclear weapons, dismissing as incomplete a U.S. intelligence report that Iran's nuclear arms program was frozen in 2003.

Sixteen U.S. intelligence agencies concluded in a comprehensive study published on December 3 that Iran had stopped activities aimed at making nuclear weapons in 2003, though it continues to enrich uranium for nuclear fuel.

The National Council of Resistance of Iran (NCRI), which first exposed Iran's nuclear fuel program in 2002, said it published information three years ago alleging that Tehran had restarted weapons-related work after a short break.

NCRI officials said they checked back with sources inside Iran after the U.S. National Intelligence Estimate (NIE) was released, and those informants reported that work on nuclear weapons was still being pursued at three sites.

The clerical regime is continuing its drive to obtain nuclear weapons, Mohammad Mohaddessin of the France-based group, listed as a terror organization in the United States, told a news conference in Brussels.

The NIE report concluded that Iran had not restarted its nuclear weapons program as of mid-2007. The halt applied to work on explosive device components and to uranium conversion activities, it said.

That conclusion contradicted earlier assertions by the Bush administration that Tehran was determined to develop the bomb.

Analysts say it could complicate the U.S. drive for a new round of U.N. sanctions against Iran.

Tehran welcomed the report as proof Bush wanted to deceive the world about a nuclear arms program it has denied pursuing. But major powers said their policy remained one of seeking negotiations with Tehran over inducements to suspend uranium enrichment, while threatening it with sanctions.


Mohaddessin said the NCRI agreed with the NIE assessment that activities were suspended in 2003, and specified that in March 2003 Iran closed down a weaponization site in Lavisan, northeast Tehran, fearing it might be detected.

But it transferred the weapons activities to a new site in Lavisan and later to two additional sites, information the NCRI had made public from November 2004 onwards, he said.

Asked how Washington's entire intelligence community and the U.N. nuclear watchdog, the IAEA, could have missed evidence of this, he said: Exactly as they missed Natanz (Iran's uranium enrichment plant) and (the original) Lavisan.

Mohaddessin said the new Lavisan site hosted research on laser enrichment of uranium, while two whole-body counters -- used for detecting radiation -- were in use at a university in the central city of Isfahan and a hospital outside Tehran.

He said Iran continued research after 2003 on a bomb initiator and on other technologies that could be used in a nuclear bomb.

Mohaddessin acknowledged that some of those technologies had civilian uses but concluded: It is very obvious that the clerical regime resumed its military activities in 2004.

NCRI officials said their sources included people with contacts with high-ranking Iranian officials, military officers and the Revolutionary Guard, as well as individuals working inside the new Lavisan facility.

The NCRI's armed wing, the People's Mujahideen organization of Iran (PMOI), is banned in the United States and the EU.

The PMOI has bases in Iraq. It began as a leftist-Islamist opposition to the late Shah but fell out with Shi'ite clerics who took power after the 1979 Islamic revolution.

Western analysts say the PMOI has little support in Iran because of its collaboration with Iraq during the 1980-88 Iran-Iraq war.

(Editing by Tim Pearce)