Nuclear group: Time Iran would need to make uranium for a bomb 'too short'

Iran may need only a month to produce enough weapons-grade uranium for a nuclear bomb, a U.S.-based anti-proliferation group says in a new assessment of Tehran's enrichment program.

But that is only if the country were able to take the most extreme and direct enrichment path, says the Institute for Science and International Security in Washington. Under other scenarios, it would take significantly longer for Tehran to produce the material -- more than 11 months in one estimate.

And that would still not give Iran a nuclear bomb. Turning enriched uranium into a usable weapon would take a great deal more time, the report suggests.

The warning Thursday from ISIS was released as U.S. lawmakers consider legislation that could tighten sanctions on Iran until a deal is reached on the Middle Eastern country's nuclear program.

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It also comes after talks resumed on the program between Iran and six world powers -- the United States, Russia, China, France, Germany and Britain -- known as the P5+1.

The report examines scenarios under which Iran could produce enough weapons-grade uranium to make a nuclear bomb -- and "break out" of the Nuclear Nonproliferation Treaty.

In a statement that described the report as "extremely alarming," House Majority Leader Eric Cantor, R-Virginia, urged the United States to consider all options, including the use of military force, "to prevent Iran from acquiring the world's most dangerous weapons. We all want negotiations to succeed, but time is clearly running out."

The report adds to the sense of urgency over the talks, said Shashank Joshi, a research fellow at the London-based Royal United Services Institute. But, he noted, not all analysts share the group's view. He said it would be difficult for Iran to secretly work toward a bomb without kicking out international inspectors.

ISIS appears to have overestimated the pace of Iran's nuclear development in the past, however. In a December 2008 report, it said Iran was expected to reach a nuclear weapons capability "during 2009 under a wide variety of scenarios."

The Iranian government declared the report baseless.

"This is a huge lie because, according to Iran's Supreme Leader Ayatollah Seyed Ali Khamenei, production, storage and use of weapons of mass destruction are haraam (forbidden by Islam)," said Marzieh Afkham, a Foreign Ministry spokeswoman. "Weapons of mass destruction have no place in the Islamic Republic's doctrine. This kind of report is totally false."