US Energy Secretary Chris Wright told lawmakers that Iran is “frighteningly close” to constructing nuclear weapons, insisting that the country is “weeks away” from enriching one ton of its uranium to weapons-grade levels, CNN reported.

“Frighteningly close. They are weeks, a small number of weeks away to enrich that to weapons-grade uranium,” CNN quoted Wright as saying at the U.S. Senate Armed Services Committee at a hearing. “There’s still a weaponization process that happens after that, but they’re quite close to constructing nuclear weapons.”

Enriching uranium above a certain threshold — around 90% — means it can be used to create nuclear weapons. Asked by Democratic Sen. Richard Blumenthal about the status of Iran’s other reported 11 tons of uranium, Wright said the levels of enrichment ranged up to 60%, though Iran has “a lot of” 20% enriched uranium, which he called “very concerning.”

Blumenthal then pressed Wright on whether President Donald Trump would have to go after all of Iran’s uranium stockpiles in order to stop the enrichment.

“I think that’s the wise strategy,” Wright said. “Ultimately, the goal is to prevent future enrichment of uranium as well. Yes, to have a safe world, we need to end their nuclear program.”

Multiple Trump administration officials have cited Iran’s enriched uranium stores as part of the rationale for the war with Iran. Trump has also said he wants Iran to surrender its enriched uranium in order to reach a deal to end the conflict.

Iran officially denies pursuing nuclear weapons, maintaining that its nuclear program is solely for peaceful, civilian purposes.