U.N.: Iran conducted nuclear weapons research as recently as 2009

Oren Dorell | USA TODAY

Show Caption Hide Caption Iran deal officially begins, here are the next milestones It's been 90 days since the U.N. approved the Iran Nuclear Deal, which means the country is now tasked with reducing its nuclear program. Video provided by Newsy

The United Nations' nuclear watchdog said Tuesday it has completed its investigation of Iran’s nuclear weapons program after concluding Iran had conducted weapons' research as recently as 2009.

The announcement moves oil-rich Iran a step closer to seeing international sanctions lifted at a time when crude prices are already at a decade low. Removal of sanctions could drive prices lower by allowing global markets to tap Iran's vast oil reserves.

In a statement to the board of governors of the U.N. watchdog, the International Atomic Energy Agency (IAEA), Director-General Yukiya Amano said his investigation did not answer all outstanding questions about Iran's past research but concluded that Iran's nuclear weapons work continued until six years ago.

"The agency has no credible indications of activities in Iran relevant to the development of a nuclear explosive device after 2009," Amano said. "Nor has the agency found any credible indications of the diversion of nuclear material" in connection to such work, he said.

The agency's report is part of an agreement that the United States and five other world powers reached with Iran in July to limit its nuclear activities to peaceful purposes in return for sanctions relief.

The IAEA's conclusion that Iran conducted nuclear weapons research through 2009 counters years of Iranian claims that its nuclear program was for peaceful purposes.

Iranian Foreign Minister Javad Zarif continued those denials Tuesday as he welcomed the U.N. announcement. “Based on this resolution, it can be said unequivocally that the fake issue of so-called military dimensions of Iran’s nuclear program ... now belongs to history,” Zarif said, according to the government-owned Tasnim News Agency.

Iran's ambassador to the IAEA, Reza Najafi, told the board of governors that Iranian officials "categorically reject existence" of a prior program to develop a nuclear explosive device.

Secretary of State John Kerry welcomed the U.N. decision and said the conclusion corresponds with U.S. assessments. Closing the investigation allows the IAEA to turn its attention to monitor Iran's compliance with the nuclear agreement.

This "will in no way preclude the IAEA from investigating if there is reason to believe Iran is pursuing any covert nuclear activities in the future, as it had in the past,” Kerry said.

Iran is poised to add a half million barrels a day to the saturated world oil supply by mid-2016, once the sanctions relief goes into effect, said Sara Vakhshouri, a senior energy fellow at the Atlantic Council think tank in Washington.

Positive news on Iran’s nuclear agreement with world powers "could have a psychological downward impact on the global oil prices,” Vakhshouri said. “This could happen even before Iran increases its export volumes.”

Supporters and critics of the nuclear deal agree that world powers should maintain pressure on Iran to make sure it sticks to the terms, but they disagreed on whether Tuesday’s vote will make that task easier.

“I do think Iran will push the edges of the agreement and the international community will have to be aggressive about keeping Iran from wandering into the gray zone,” said Kelsey Davenport, director of nonproliferation policy at the Arms Control Association, a research organization that cheered the deal when it was reached.

Mark Dubowitz, an expert on Iran sanctions at foreign policy group Foundation for Defense of Democracies who has criticized the nuclear agreement as too weak, said Tuesday’s vote will likely weaken the accord further.

"The international community has let Iran off the hook,” Dubowitz said. “Iran has learned that stonewalling and intransigence will be met with a feeble international response.”

Iran’s supreme leader, Ali Khamenei, blocked further steps his country must take until after the IAEA decision. Iran is required to remove the core from its nuclear reactor at Arak, ship 98% of its enriched uranium fuel to other countries, dismantle 13,500 centrifuges that process uranium into fuel and allow the IAEA to install monitoring equipment.

Davenport said the nuclear agreement gives the IAEA inspectors greater tools to ensure Iran doesn't have a secret weapons program. Inspectors will have access to sites where nuclear activity is suspected, she said. Iran also agreed not to conduct explosive testing that in the past Iran claimed was for conventional purposes.

Davenport said that once sanctions are lifted and Iran becomes integrated in the world market the government “will have a powerful incentive to remain there, (and) to remain compliant with the deal.”

Dubowitz was skeptical. “Removing sanctions makes it much harder because we’re losing leverage to get Iran to comply,” he said.