Milley presented a much shorter timeline than officials previously have when discussing Iran’s nuclear capabilities.
He added that the U.S. won’t allow Iran to have a "fielded nuclear weapon."
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Joint Chiefs Chairman Gen. Mark Milley speaks with reporters after a virtual meeting of the Ukraine Defense Contact Group at the Pentagon May 23, 2022, in Washington. (AP Photo/Alex Brandon)
"We, the United States military, have developed multiple options for our national leadership to consider if or when Iran ever decides to develop an actual nuclear weapon," Milley said.
Officials remain concerned about Iran’s nuclear capabilities after attempts to revive the Joint Comprehensive Plan of Action, known as the Iran Nuclear Deal, which the U.S. withdrew from during the Trump administration in 2018.
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Joint Chiefs Chair Army General Mark Milley speaks with U.S. forces in Syria during an unannounced visit at a U.S. military base in Northeast Syria March 4, 2023. (REUTERS/Phil Stewart/File Photo)
Unnamed senior diplomats told Bloomberg in February Iran has accumulated uranium enriched to 84% purity, a concentration 6% below what’s needed for a weapon, marking the highest levels found by inspectors in Iran to date.
Iran had previously told the International Atomic Energy Agency (IAEA) that its centrifuges were configured to enrich uranium to a 60% level of purity.
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Former President Hassan Rouhani, second right, listens to the head of the Atomic Energy Organization of Iran, Ali Akbar Salehi, while visiting an exhibition of Iran's new nuclear achievements in Tehran, Iran, in April 2021. (Iranian Presidency Office/AP)
It remains unclear whether the material was intentionally produced or it was an unintentional accumulation within the centrifuges used to separate the isotopes.
The timeline to create a nuclear weapon remains unclear, with some experts believing it could take between six months and three years, according to The Wall Street Journal.
Gary Samore, the director of the Crown Center for Middle East Studies at Brandeis University and a former White House official during the Obama administration, told the Journal no one can tell "how quickly Iran can restart and finish the research and development work they were doing before 2003."
Col. Dave Butler, a spokesman for Gen. Milley, declined to elaborate on his assessment to Congress, telling the Journal that the "chairman’s statement speaks for itself."
Fox News Digital’s Bradford Betz contributed to this report.