US and Iran at odds over enriched uranium stockpile

President Donald Trump reaffirmed on May 22, 2026, that the United States will not permit Iran to retain its stockpile of high-grade enriched uranium. Speaking at the White House, Trump stated: “We will take it. We don't need it, we don't want it. We may destroy it after taking it, but we will not let them keep it.”

However, on the same day, Reuters reported, citing two anonymous Iranian sources, that Supreme Leader Mojtaba Khamenei had issued a directive barring the transfer of enriched uranium out of the country. One of the sources said: “The Supreme Leader's directive, and consensus within the government apparatus, is that the enriched uranium stockpile must not leave the country.”

The fate of approximately 440 kilograms of uranium enriched to 60 percent, believed to be in Iran's possession, remains a critical sticking point in peace negotiations between the US and Iran. According to nuclear experts, although uranium enriched to 60 percent is still far from the 90 percent threshold needed for nuclear weapons, reaching that higher level becomes significantly faster once the 60 percent mark is achieved.

Responses from various parties

Reuters also reported, citing unnamed Israeli officials, that President Trump had committed to Israel that Iran's enriched uranium stockpile would be removed from the country and that any peace agreement would include this provision. Meanwhile, Iranian Foreign Minister Abbas Araghchi stated earlier in May that Iran and the US had reached an “impasse” over Iran's “enriched materials” and that the issue had been “pushed back” to later stages of negotiations.

Background of Iran's nuclear program

Tehran has long maintained that its nuclear program is for civilian purposes only and that it has no intention of building nuclear weapons. Iran signed the Joint Comprehensive Plan of Action (JCPOA) with the US in 2015, agreeing to limit its nuclear program in exchange for sanctions relief. However, President Trump withdrew the US from the agreement in 2018 and reimposed sanctions, despite international inspectors confirming Iran's compliance.

After the US withdrawal from the JCPOA and the 2021 bombing of the Natanz nuclear facility, which Iran blamed on Israel, Iran decided to enrich uranium from the permitted 3.67 percent to nearly 60 percent. Iran is now believed to possess about 440 kilograms of uranium enriched to 60 percent, enough to produce more than 10 nuclear warheads if further enriched to 90 percent, according to International Atomic Energy Agency (IAEA) Director General Rafael Grossi.

Options for handling and safety of transportation

The US wants Iran to hand over this uranium, but Iran has previously been open to considering transferring it to a third party. Now, Supreme Leader Khamenei's directive has completely banned sending the uranium abroad. Some reports indicate that in February 2026, during informal talks in Geneva, Iran proposed “downblending” the stockpile from 60 percent to 3.67 percent in an irreversible process.

Technically, gaseous uranium hexafluoride is extremely hazardous, capable of producing toxic fluoride compounds if leaked. The IAEA has specific procedures for safely transporting enriched uranium, using robust, standard 30B steel cylinders that withstand high pressure and temperature, and are designed with small dimensions to prevent the risk of uncontrolled nuclear chain reactions.

Historically, the US has transported high-grade enriched uranium to Canada for medical isotope production and carried out a covert operation called Project Sapphire in 1994, moving approximately 600 kilograms of weapons-grade uranium from Kazakhstan to the United States.