How Tehran's Nuclear Commitments Pushed The US-Iran Deal Into Last-Minute Deadlock

Last Updated:April 14, 2026, 08:44 IST

Talks between the US and Iran in Islamabad failed to secure a breakthrough after sharp differences emerged over Tehran’s nuclear clause.

A potential breakthrough in US-Iran negotiations collapsed at the last moment after sharp differences emerged over Tehran’s nuclear commitments, with the duration and scope of uranium enrichment restrictions becoming the central obstacle to a deal.

During high-stakes talks in Islamabad, the United States proposed that Iran accept a 20-year suspension of nuclear activity, arguing that long-term limits were necessary to ensure Tehran could not develop a nuclear weapon capability “not just now, not just two years from now, but for the long term," Vice President JD Vance said before departing Pakistan.

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The Wall Street Journal quoted officials familiar with the discussions as saying that Washington’s proposal stopped short of demanding a permanent ban but sought a lengthy moratorium on enrichment activities, a compromise intended to provide assurances while allowing Iran to maintain that it had not permanently surrendered its nuclear rights under the Nuclear Nonproliferation Treaty.

Iran, however, countered with a significantly shorter timeline, proposing a pause lasting up to five years or a “single digit" number of years, according to sources involved in the negotiations, Axios reported.

URANIUM STOCKPILE EMERGES AS CORE FLASHPOINT

Beyond the duration of the freeze, another major sticking point involved the fate of Iran’s existing stockpile of highly enriched uranium.

US negotiators demanded that Iran remove nearly 970 pounds of near-bomb-grade uranium from the country to ensure it could not be diverted for weapons use.

Iran rejected that demand, insisting the nuclear material remain on its soil while offering instead a “monitored process of down-blending" to reduce enrichment levels to non-weapons-grade purity, the Axios report mentioned.

The disagreement over enrichment and stockpile removal ultimately prevented the two sides from reaching an agreement, according to officials involved in the negotiations.

An Iranian member of parliament involved in the talks, Seyyed Mahmoud Nabavian, said the US demands on enrichment and uranium stockpiles were the main reasons a deal could not be reached.

TALKS SHOW SIGNS OF PROGRESS DESPITE DEADLOCK

Despite the impasse, officials on both sides indicated that negotiations had made progress and could continue in the coming days, with mediators attempting to bridge the final gaps.

Vance said there were “some good conversations" in Islamabad, but indicated Iran had “didn’t move far enough" to secure an agreement.

He added that the “big question from here on out is whether Iranians will have enough flexibility."

Behind the scenes, Pakistani, Egyptian and Turkish mediators have intensified diplomatic efforts to prevent the collapse of the ceasefire expected to expire on April 21.

Turkish Foreign Minister Hakan Fidan suggested that early negotiating positions are often maximalist, adding that parties usually move toward compromise over time.

“Initial positions are always somewhat maximalist. Later, the parties try to find common ground with the support of mediators," Fidan said, while cautioning that treating enrichment as an “all or nothing" issue could create a serious obstacle.

TRUMP ADMINISTRATION SEEKS STRONGER TERMS THAN PAST DEALS

The latest proposal reflects Washington’s effort to avoid a repeat of the 2015 Joint Comprehensive Plan of Action (JCPOA), which allowed Iran to gradually resume enrichment activity after certain deadlines.

The current US framework instead aims to ensure a prolonged halt to nuclear activity, extending beyond the current political cycle in Washington.

Experts note that previous diplomatic efforts, sanctions and covert operations have historically sought to delay Iran’s progress toward developing nuclear weapons capability.

“If they could get Iran to suspend for even a few years, that is superior to what we got in the J.C.P.O.A.," said Rob Malley, who was part of the 2015 negotiating team.

BLOCKADE PRESSURE AND DIPLOMATIC CLOCK

Negotiations are unfolding amid mounting economic pressure on Tehran, with Washington highlighting a naval blockade as leverage to push Iran toward concessions.

White House officials said the pressure campaign could increase Iran’s urgency to reach a deal, while Tehran has also raised demands related to access to frozen funds linked to oil sales restricted under sanctions.

Officials indicated that another round of in-person talks is under consideration, though no formal meeting has been finalised.

For now, the nuclear clause, particularly the duration of enrichment limits and control over uranium stockpiles, remains the decisive factor preventing a last-minute diplomatic breakthrough, even as mediators attempt to keep negotiations alive before the ceasefire deadline.

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