BRUSSELS, Feb 20 (Reuters) - An Iranian opposition group called on Wednesday for the U.N. nuclear watchdog to immediately inspect facilities in Iran which it said were at the core of an accelerated nuclear weapons programme. The National Council of Resistance of Iran dismissed a December U.S. National Intelligence Estimate that Tehran stopped trying to make a nuclear warhead in 2003, shortly after the group first revealed the country’s nuclear enrichment activity. It charged that Iran had established a new command and control centre for the programme coded-named Lavizan-2 at Mojdeh on the southeastern outskirts of Tehran last April, near the site of a previous facility razed after its exposure. The NCRI said the Iranian government was also actively pursuing production of nuclear warheads at a complex code-named B1-Nori-8500 at Khojir about 20 km (12 miles) further southeast. Iran insists its nuclear programme is peaceful and aimed at producing electricity, but its concealment of uranium enrichment activities until 2003 and curbs on U.N. inspections have fuelled international suspicions that it is intended to produce weapons. At a Brussels news conference, NCRI foreign affairs chief Mohammad Mohaddessin said his information came from "hundreds" of sources including people working at the sites and within the offices of the Iranian leadership and bureaucracy. He showed satellite images and called on the International Atomic Energy Agency (IAEA) to inspect the sites immediately and interview the scientists running them. "The Iranian regime is undoubtedly developing the nuclear bomb. None of the essential work has been halted ... All three parts have been speeded up," he said, referring to uranium enrichment, weaponisation and missile development. "TIME IS RUINNING OUT" "We would like to urgently ask the IAEA ... to immediately send inspectors to the sites," he said. "Time is running out to stop the regime acquiring a nuclear bomb. If we do not act today, tomorrow might be too late." Following a familiar pattern, the charges were issued ahead of the IAEA’s latest report on Iran, due on Friday. IAEA spokeswoman Melissa Fleming said in Vienna: "We are aware of this but have no comment at this point. As with all new information coming our way, (our) analysts take a serious look and decide whether it would warrant a follow-up." The NCRI, the political arm of the Iraq-based People’s Mujahideen guerrilla group, is on the U.S. and European Union lists of outlawed terrorist organisations. Diplomats say Washington, hoping to extract explanations from Iran, authorised the IAEA in January to present Tehran with intelligence showing it had attempted to weaponise its nuclear activity, but Iran was still denying this. Mohaddessin said the release of the U.S. National Intelligence Estimate could have been motivated by internal U.S. politics in the run-up to the presidential election. Alireza Jafarzadeh, who first publicised the secret nuclear effort, told journalists Iran’s alleged weapons programme was "probably at the most advanced stage" since its launch in 1983. Mohaddessin said the Khojir site was under the charge of missile expert Mehdi Naghiyan Fesharaki, who was transferred there two years ago. "This means the regime is getting to the point of connecting nuclear weapons to missiles," he said. Since it revealed the Iranian nuclear programme in 2002, the NCRI’s follow-up efforts to show Tehran is seeking to make bombs have fallen short for lack of verifiable evidence. Its charges are hard to check due to Iran’s ban on intrusive snap inspections beyond a few declared nuclear production sites. Photo by Reuters: Alireza Jafarzadeh shows a map at a news conference in Brussels, February 20, 2008, of what NCRI says is a clandestine nuclear site in Iran.