Iran has continued to produce highly enriched uranium at a pace of roughly one nuclear weapon’s worth per month over the past three months, despite ongoing diplomatic efforts with the United States to negotiate a new nuclear deal, according to a confidential report by the International Atomic Energy Agency (IAEA) seen by The Wall Street Journal.

The report, prepared for the IAEA’s Board of Governors meeting next week, underscores Tehran’s persistent defiance of international demands to curb its nuclear program, raising concerns about the prospects for a diplomatic resolution.

The IAEA report, dated May 29, 2025, estimates that Iran’s stockpile of uranium enriched to 60% purity has reached 408 kilograms (approximately 900 pounds) as of May 15, a significant increase from the 274.8 kilograms (605.8 pounds) reported in February 2025.

This represents a nearly 50% jump in just three months, with Iran producing roughly 45 kilograms per month of near weapons-grade material.

Uranium enriched to 60% is a short technical step from the 90% purity required for weapons-grade material, which the IAEA defines as sufficient for a nuclear weapon at around 42 kilograms if further enriched.

U.S. officials estimate that Iran could convert its current stockpile into enough weapons-grade material for a single nuclear weapon in less than two weeks.

The report also notes that Iran’s total enriched uranium stockpile has grown to 9,147.0 kilograms (20,165 pounds), an increase of 852.6 kilograms since the last quarterly report in February.

This escalation comes despite Iran’s engagement in multiple rounds of nuclear talks with the U.S., mediated by Oman and held in locations including Muscat and Rome.

The IAEA expressed “serious concern” over Iran’s continued production of highly enriched uranium, noting that it is the only non-nuclear-weapon state to produce such material at this scale.

The buildup of Iran’s uranium stockpile coincides with heightened tensions between Tehran and Washington, particularly following the re-election of U.S. President Donald Trump, who has vowed to prevent Iran from acquiring nuclear weapons.

During his first term, Trump withdrew the U.S. from the 2015 Joint Comprehensive Plan of Action (JCPOA), which had limited Iran’s uranium enrichment to 3.67% purity and capped its stockpile at 300 kilograms in exchange for sanctions relief.

After the U.S. withdrawal in 2018, Iran began violating these limits, and by 2020, it was enriching uranium to 60% purity, a level far beyond what is needed for civilian nuclear power.

Recent negotiations, led by U.S. envoy Steve Witkoff and Iranian Foreign Minister Abbas Araghchi, have failed to produce a breakthrough.

Iran has insisted on continuing uranium enrichment as a non-negotiable “red line,” with Araghchi stating on May 21, 2025, that “uranium enrichment in Iran will continue—with or without an agreement.”

The U.S., however, has demanded that Iran halt enrichment entirely, a condition not even required under the original JCPOA.

Trump has publicly floated the possibility of military action, stating, “There’s two ways to stopping them: with bombs or a written piece of paper. I would love to make a deal with them without bombing them.”

Iran’s Supreme Leader, Ayatollah Ali Khamenei, has sent mixed signals.

In August 2024, he suggested that there was “no harm” in engaging with the U.S., but more recently, he described negotiations as “not intelligent, wise, or honorable,” particularly in response to Trump’s threats.

The IAEA report notes that Iran has not reconsidered its September 2023 decision to bar some of the agency’s most experienced inspectors, further limiting oversight of its nuclear facilities.

The IAEA’s findings come amid growing regional tensions, exacerbated by Iran’s support for groups like Hamas and Hezbollah and recent missile exchanges with Israel.

Israel has repeatedly threatened to strike Iran’s nuclear facilities if it perceives an imminent threat, a scenario that could escalate into a broader conflict, potentially involving the U.S. Robert Einhorn, a former State Department official, noted that Iran’s enrichment surge is likely a strategic move to bolster its negotiating leverage and project the image of a country capable of rapidly developing nuclear weapons.

“Iran believes it needs a near-weapons capability for strategic reasons,” Einhorn said.

The IAEA report also highlights Iran’s lack of cooperation on unresolved issues, including the origin of man-made uranium particles found at undeclared sites in Varamin and Turquzabad.

These findings, dating back to a 2018 Israeli intelligence operation, suggest that Iran may have conducted undisclosed nuclear activities, further eroding trust in its claim that its nuclear program is solely for peaceful purposes.