Iran nuclear timeline unchanged despite recent attacks as Strait of Hormuz tensions threaten ceasefire

May 5, 2026

U.S. intelligence assessments indicate Iran still needs up to a year to build a nuclear weapon, unchanged from estimates following last summer's U.S.-Israeli strikes on nuclear facilities at Natanz, Fordow, and Isfahan. Despite a two-month war launched by President Trump in part to prevent Iranian nuclear weapons development and an April 7 ceasefire, Iran's nuclear timeline remains broadly the same, with recent attacks focusing on conventional military targets rather than nuclear infrastructure. The U.N. nuclear watchdog cannot verify the location of 440 kilograms of 60% enriched uranium—enough for 10 bombs if further enriched—believed stored in deeply buried underground sites at Isfahan that U.S. munitions cannot penetrate. Meanwhile, escalating incidents in the Strait of Hormuz, where Iran has blocked 20% of world oil supplies, threaten the fragile ceasefire between the two nations.

U.S. intelligence assessments of Iran's nuclear weapon timeline

▪The assessments of Tehran's nuclear program remain broadly unchanged even after two months of war that U.S. President Donald Trump launched in part to stop Iran from developing a nuclear bomb.
▪U.S. intelligence agencies concluded prior to June's 12-day war that Iran likely could produce enough bomb-grade uranium for a weapon and build a bomb in around three to six months.
▪Following June strikes by the U.S. on Natanz, Fordow and Isfahan nuclear complexes, U.S. intelligence estimates pushed Iran's nuclear weapon timeline back to about nine months to a year.

Military strikes on Iran's nuclear and conventional capabilities

▪The latest U.S. and Israeli attacks that began on February 28 have focused on conventional military targets.
▪The war between the U.S. and Iran has stalled since both countries agreed an April 7 truce to pursue peace.
▪Israel has hit a number of significant nuclear facilities during the war that began on February 28.

Challenges in eliminating Iran's nuclear program and remaining threats

▪The U.N. nuclear watchdog believes that about half of Iran's 440 kilograms of 60% enriched uranium was stored in an underground tunnel complex at the Isfahan Nuclear Research Center.
▪The U.N. nuclear watchdog has been unable to verify the whereabouts of some 440 kilograms of uranium enriched to 60%.
▪The International Atomic Energy Agency assesses Iran's total highly enriched uranium stockpile would be enough for 10 bombs if further enriched.
▪Iran has choked traffic through the Strait of Hormuz, blocking some 20% of world oil supplies and igniting a global energy crisis.
▪U.S. intelligence agencies and the IAEA say Tehran halted a warhead development effort in 2003.
▪Some experts and Israel contend that Iran secretly preserved key parts of its warhead development program after 2003.