WASHINGTON — President Donald Trump on Monday appeared to undercut a proposal that was offered by his special envoy to Iran, saying he will insist that Tehran fully dismantle its nuclear enrichment program as part of any deal to ease crushing sanctions.

Trump and Steve Witkoff, who is leading the negotiations for the U.S., have repeatedly offered inconsistent public messages about whether Iran would be allowed to retain the capacity to enrich uranium to lower levels for civilian purposes. The Trump administration maintains that it will not allow Iran to develop a nuclear weapon.

The negotiations have been framed by Trump as both countries’ best chance to avoid direct military conflict over Iran’s nuclear program. Tehran, which denies seeking a nuclear weapon, has insisted that it will not agree to any deal that fully scraps its enrichment program.

“Under our potential Agreement — WE WILL NOT ALLOW ANY ENRICHMENT OF URANIUM!” Trump wrote on social media.

Addressing the seeming contradiction, a White House official said Trump was speaking the “cold, hard truth.” The official said the terms the U.S. gave the Iranians were “very tough” and would make it impossible for them to obtain a nuclear bomb.

Trump’s post comes after media reports that Witkoff’s latest proposal to Tehran would allow Iran to retain low levels of enrichment for civilian uses like nuclear medicine and commercial power if it agrees to shut down its heavily protected underground sites for a period of time. The U.S. and Iran have engaged in several rounds of direct nuclear talks for the first time in years.

Senior officials — including Witkoff and Trump himself — have said within the last few weeks that Iran would not be able to keep enriching uranium at any level.

The proposal, reported by Axios and confirmed by a U.S. official, called for the creation of a regional consortium to handle uranium enrichment for civilian uses — a plan first studied more than a decade ago in negotiations that led to the 2015 Iran nuclear deal.

Trump was sharply critical of that agreement — which also allowed set limits on uranium enrichment but permitted Iran to maintain such a capacity — and withdrew the U.S. from it in 2017 during his first term.

The officials spoke to The Associated Press on condition of anonymity to discuss private diplomatic negotiations.

The International Atomic Energy Agency found that Iran has further increased its stockpile of uranium enriched to near weapons-grade levels since its last update in February, according to a confidential report released by the U.N. nuclear watchdog on Saturday.