FACTBOX: U.S. says Iran halted nuclear arms program

(Reuters) - U.S. intelligence agencies concluded in findings released on Monday that Iran stopped its nuclear weapons development program in 2003. Following are highlights of the National Intelligence Estimate's key judgments.

-- Iran had a nuclear weapons program but halted it in 2003 and had not restarted it as of mid-2007. The halt applied to design and engineering of an explosive device, such as fuses or shielding, and to covert uranium-conversion activities, according to senior intelligence officials. Other activities such as civilian uranium enrichment and missile development continue.

-- Iran is keeping open the option of developing nuclear weapons, but U.S. intelligence agencies "do not know" whether it currently intends to develop nuclear weapons. This is a major change from a 2005 intelligence estimate which concluded that Iran was "determined to develop nuclear weapons."

-- The weapons program was halted in response to international pressure, meaning Tehran may be more susceptible to influence than previously thought.

-- Tehran's decisions on nuclear weapons are guided by a consideration of the costs and benefits of its actions, rather than "a rush to a weapon" regardless of political and other consequences.

-- Iran would be technically capable of producing enough highly enriched uranium for a nuclear weapon by late 2009, but this is unlikely and a time frame of 2010-2015 is more likely.

-- Iran still faces significant problems operating the centrifuges needed to make enriched uranium, despite progress this year installing them at its Natanz facility.

-- It will be hard to persuade the Iranian leadership to renounce nuclear weapons development altogether.

-- Iran may have imported at least some weapons-grade nuclear fuel but not enough to make a weapon. It cannot be ruled out that Iran has acquired from abroad, or will acquire, a nuclear weapon or sufficient nuclear fuel to make one.