US, Iran spar over uranium enrichment, raising hurdle to deal and oil sanctions relief

The US and Iran are diametrically opposed to each other on whether Tehran should end all its uranium enrichment as part of a nuclear deal, in a spat that stands in the way of removing US oil sanctions.

"We have one very, very clear red line, and that is enrichment," Steve Witkoff, US special envoy to the Middle East, said on ABC News on May 18. "We cannot allow even 1% of an enrichment capability," because enrichment enables weaponization, he said.

The US is 100% committed to the red line of no enrichment, White House Press Secretary Karoline Leavitt said on May 19. "The president, Special Envoy Witkoff, Secretary [of State Marco] Rubio have made that incredibly clear, not just to the American public but also in those discussions that Special Envoy Witkoff has had directly with the Iranians," Leavitt said.

But any demand to stop enrichment is a non-starter for Iran.

"Our position regarding the enrichment is very clear," Majid Takhtravanchi, deputy foreign minister for political affairs, said on May 19. "If this is going to be their position, it's obvious that this will practically go nowhere," he said.

Iran is open to participating in an enrichment consortium with other countries in the region, Esmaeil Baghaei, a foreign ministry spokesperson, said on May 19. But, he noted, "If it is brought up so that enrichment wouldn't be carried out in Iran and we would refrain from it, this isn't going to happen."

The impasse on enrichment could be a stumbling block for a nuclear deal that would lead to oil sanctions relief for Iran.

US President Donald Trump reimposed maximum pressure sanctions on Iran in February. Since Trump returned to the White House, the Treasury Department has issued more than 250 sanctions on Iran.

Still, Iran's crude production is on the rise. Iran produced an average of 3.23 million b/d of crude in the first four months of 2025, up from an average of 3.17 million b/d in 2024, according to data from the Platts OPEC+ survey by S&P Global Commodity Insights.

Dimming outlook

Witkoff's comments show that hopes of an early deal look tough, and there may be many innings ahead, Rachel Ziemba, senior adviser for Horizon Engage, said. As for impacts on the oil market, this development probably further reverses some recent hopes of easing and increases the risk of continued marginal sanctions tightening, she said

Ellen Wald, president of Transversal Consulting, agreed that the comments put the brakes on the process, but they don't necessarily mean that any enrichment is off the table or that negotiations are over, she said.

The US and Iran first made opening statements showing they were willing to talk, and they are now in the second phase of negotiations, where each party is showing strength by making harsh statements, she said.

"When each side is done showing their feathers and finally sits down to (maybe) hammer things out, I can't imagine that civilian-level enrichment won't be on the table for Iran," Wald said.

Rachel Ziemba, a senior adviser at Horizon Engage, raised a similar point. "It's still not clear where Trump really lands on the issue, and it could be that Witkoff is floating this trial balloon ahead of the next round of talks as a tougher opening position," she said.

But there is a danger in how far the US can push this message in Iran, said Alex Vatanka, a senior fellow at the Middle East Institute. "If that kind of message becomes more pronounced, then it's going to be harder to roll it back and engage in diplomacy," he said. "It's a very prickly regime in Tehran."