New York: Iran did shut down its nuclear weapons program in 2003 but restarted it a year later, dispersing the equipment to thwart international inspectors, an overseas Iranian opposition group told the Wall Street Journal.

The group, the National Council of Resistance of Iran (NCRI), exposed the country's nuclear-fuel programme in 2002 and now believes a recent US analysis is giving the wrong impression that Iran's nuclear programme is not an urgent threat, the newspaper reported on Tuesday.

The group  said the facility was broken into 11 fields of research, including projects to develop a nuclear trigger and shape weapons-grade uranium into a warhead, the paper said.

"They scattered the weaponisation program to other locations and restarted in 2004," Mohammad Mohaddessin, the NCRI's foreign affairs chief, told the Journal.

The US National Intelligence Estimate published last week said Iran's weapons programme was frozen in 2003, contradicting an earlier report that the Islamic Republic was determined to build a nuclear bomb.

Israeli Prime Minister Ehud Olmert disagreed, saying Israel believes Iran will have the resources to create a nuclear weapon by 2010. But the estimate dampened any enthusiasm among Russia and China for more UN sanctions against Iran.

The NCRI is listed by the United States as a terrorist organisation, and its armed wing is seen as a terrorist group by the European Union. The NCRI has had a mixed record of accuracy with its nuclear claims about Iran, the Journal said.

The NCRI does agree that Iran's Supreme National Security Council decided to shut down its most important nuclear weapons research centre in eastern Tehran, called Lavisan-Shian, in August 2003, the Journal said.