The U.S. intelligence community has assessed that Iran acquired all the technology required for nuclear weapons.
Officials said the community determined that the Teheran regime has refined skills and technology to enable Iran to quickly assemble nuclear weapons, including warheads for ballistic missiles. They said the community assessed that the production of such weapons depended on the Iranian leadership.
"Such a decision will reside with the supreme leader, and at this point, we don't [know] if he'll eventually decide to build nuclear weapons," National Intelligence director James Clapper said.
On May 22, the International Atomic Energy Agency reported that Teheran accelerated construction of a nuclear research reactor at the heavy water plant near Arak. The agency also reported an increase in uranium refinement capacity -- including nearly 700 IR-2M centrifuges -- at Natanz since February 2013.
In an assessment submitted to Congress in April 2013, Clapper, who oversees the 16-agency intelligence community, said Teheran has been developing technical expertise in every area of nuclear weaspons development. He cited uranium enrichment, nuclear reactors, weaponization and ballistic missiles.
"These technical advancements strengthen our assessment that Teheran has the scientific, technical and industrial capacity to produce nuclear weapons," the intelligence assessment said. "So, the central issue is its political will to do so."
The assessment, submitted by Clapper to the Senate on April 11, did not appear to reflect statements by either the Israeli or U.S. governments. In 2013, both President Barack Obama as well as Prime Minister Binyamin Netanyahu said Iran required another year for nuclear weapons capability.
The latest U.S. intelligence assessment said Iran, with the largest ballistic missile arsenal in the Middle East, has been progressing toward the production of weapons-grade uranium. Still, Clapper said the community ruled out the prospect that Teheran could assemble a nuclear warhead from uranium stockpiles under the supervision of IAEA.
"We judge Iran's nuclear decision-making is guided by a cost-benefit approach, which offers the international community opportunities to influence Teheran," Clapper said. "It wants to advance its nuclear and missile capabilities and avoid severe repercussions -- such as a military strike or regime threatening sanctions."
The U.S. assessment said Iran was expected to use one of its intermediate-range ballistic missiles, such as the liquid-fueled Shihab-3 or solid-fuel Sejil-2, as the delivery system for a nuclear weapon. The assessment did not rule out the development of an Iranian intercontinental ballistic missile.
"We judge Iran would likely choose a ballistic missile as its preferred method of delivering a nuclear weapon, if one is ever fielded," the assessment said. "Iran's ballistic missiles are capable of delivering WMD. In addition, Iran has demonstrated an ability to launch small satellites, and we grow increasingly concerned that these technical steps-along with a regime hostile toward the United States and our allies-provide Teheran with the means and motivation to develop larger space-launch vehicles and longer-range missiles, including an intercontinental ballistic missile."