Top US military leaders told a Senate committee hearing Thursday that Iran could produce a nuclear weapon in several months once a decision is made.

Defense Secretary Lloyd Austin and Chairman of the Joint Chiefs Gen Mark Milley testified before the Senate Defense Appropriations subcommittee, where they called for budgetary support in the face of Russian, Chinese and Iranian threats.

“Iran threatens to push the Middle East yet again into instability by supporting terrorists and proxy forces and they continue to improve the capability to produce a nuclear weapon,” Gen. Milley said.

“From the time of Iranian decision by the Supreme Leader, Iran could produce enough fissile material for a nuclear weapon in less than two weeks from time of decision. It will take several more months to produce an actual nuclear weapon. United States policy remains the same. United States remains committed that Iran will never have a nuclear weapon,” he added.

Although this has always been the Biden administration’s position, Gen. Milley’s previous testimony at the House Appropriations subcommittee on Defense in March had raised questions.

Gen. Milley at the time said that “the United States remains committed as a matter of policy that Iran will not have a fielded nuclear weapon.”

The term “fielded” led to questions about what the Biden administration’s policy exactly is regarding Iran becoming a nuclear power. Previously, President Joe Biden and all top officials had repeatedly said that US policy is not to allow the Islamic Republic to acquire a nuclear weapon, threatening that all options were on the table.

It was not clear what Gen. Milley meant by a “fielded” nuclear weapon. Did it mean the administration would allow Iran to build a bomb but not “field” it, which in essence is a vague concept.

Being a nuclear threshold state is a familiar concept, meaning that a country has the fissile material and the knowhow to build a nuclear bomb but has not decided to do so, but once a bomb is produced, it is not clear what the difference would be between a bomb in the basement and one “fielded.”

But in the Senate testimony on Thursday both Austin and Milley were clear that the administration is committed to prevent any Iranian nuclear weapon.

Secretary Austin in response to a question by Senator Susan Collins also emphasized that his responsibility is to present options to the President for making sure that the United States can prevent Iran from building a bomb.

Iran began to breach the low-level uranium enrichment it was allowed under the 2015 nuclear accord, the JCPOA, when former President Donald Trump withdrew from the agreement and imposed economic sanctions in 2018. But Tehran accelerated the enrichment, stockpiling 20-percent and 60-percent enriched uranium once the Biden administration began talks in early 2021 to revive the JCPOA. Currently it is believed that Iran has enough enriched fissile material for 2-5 nuclear bombs.

Israel has repeatedly vowed to resort to military force to stop Iran from crossing the threshold and has reportedly been behind several sabotage attacks against Iran’s nuclear facilities since July 2020.

The US has expanded military cooperation with Israel and regional Arab states in the past two years, conducting large military drills with the Israeli armed forces in January.