The claims run counter to a US intelligence report released in December which said Iran halted its nuclear weapons programme in 2003.
The claims run counter to a US intelligence report released in December which said Iran halted its nuclear weapons programme in 2003.
That US report led to calls from Tehran, and some other quarters, for UN sanctions against the Iranian regime to be dropped.
"The Iranian regime is undoubtedly developing a nuclear bomb," said Mohammad Mohadessin, a leader of the exiled National Council of Resistance of Iran.
He presented reporters in Brussels with information he said had been collected on two sites in Iran on top secret studies on nuclear warheads.
The site at Khojir, in a Tehran suburb, is an Iranian defence ministry missile-research site which is developing a nuclear warhead for medium-range missiles, he said.
The other facility, in another Tehran suburb, was described as the "command and control centre" for production of a nuclear bomb.
Mohadessin said the revelations had been handed over to the International Atomic Energy Agency in Vienna on Tuesday.
North Korean experts are cooperating with the Iranian regime in the project, the Paris-based group said.
"The clerical regime (in Iran) has not ceased its nuclear weapons programme, rather it has expedited its activities and the Islamic Revolutionary Guard Corps has taken greater control of the programme," said Mohadessin, chairman of the group’s foreign affairs committee.
On December 3 the US National Intelligence Estimate, which represents the consensus among all 16 US spy agencies, said the Iranian nuclear weapons program was still dormant, and Tehran’s intentions unclear, but that the halt suggested Tehran was more susceptible to global pressure than had been thought.
The declassified "key findings" provided ammunition to both sides in the international dispute over the best approach to Iran, and were expected to fuel rather than quench the often bitter US debate over Iran policy ahead of the November 2008 presidential elections.
US President George W. Bush at the time warned that using force was still an option to keep Tehran from getting nuclear arms.
"Iran was dangerous. Iran is dangerous. And Iran will be dangerous if they have the knowledge necessary to make a nuclear weapon," he said at the time.
Mohadessin said Tuesday that for a while Iran had slowed down its weapons programme.
It had erased all traces of its earlier research centre in 2003 and moved over to Mojdeh, next to the Malek Ashtar university under the name "Field for Expansion of Deployment of Advanced Technologies," he said, his comments accompanied by satellite photographs to back up the claims.
Photo by Reuters: Mohammad Mohaddessin, chairman of the foreign affairs committee of the opposition National Council of Resistance of Iran (NCRI), shows a map at a news conference in Brussels, February 20, 2008, of what NCRI says is a clandestine nuclear site in Iran.