Former UN nuclear chief Hans Blix said Wednesday that he was surprised by the US intelligence agencies' conclusion that Iran has stopped developing nuclear weapons but assumed it was because they don't want to take the blame for a new war in the region. "An armed action against Iran cannot happen after this for the next few years," said Blix, who now chairs Sweden's Weapons of Mass Destruction Commission. The veteran Swedish diplomat, who tried to avert the 2003 US-led invasion of Iraq because no weapons of mass destruction had been found by UN inspectors, said the US intelligence report released Monday caught him off guard. "I was surprised," Blix told reporters. "For a rather long time we had heard very assured statements from the US side that Iran is acquiring nuclear weapons and that the program of enrichment is a part of that effort." Now, he noted, they have concluded that the process toward the weapons program was interrupted in 2003 and that they do not see such a program at the present time. Blix said the US agencies likely acted because they heard "all the rhetoric of World War III - and either we have the Iranian bomb or we have the bombing of Iran." The report on Iran followed an inaccurate 2002 assessment by US intelligence of Iraq's weapons of mass destruction program. "The intelligence services got a lot of blame for the invasion of Iraq that they had exaggerated what they saw ," Blix said. "This time they do not want to carry the responsibility." He said he didn't know what evidence the US intelligence agencies have that proves the Iranians abandoned their weapons program. Blix, who formerly headed the International Atomic Energy Agency, said that's further than the IAEA has gone. "The IAEA doesn't say there is nothing. They simply say we have not seen any evidence of it," he said. "Proving the negative is very difficult if at all possible."