After Iran talks falter, the big question is what happens next?

Twenty-one hours was not enough to end 47 years of hostility between Iran and the US, writes the BBC's Lyse Doucet. After Iran talks falter, the big question is what happens next? Copyright current_year BBC. All rights reserved. The BBC is not responsible for the content of external sites. Read about our approach to external linking. Copyright current_year BBC. All rights reserved. The BBC is not responsible for the content of external sites. Read about our approach to external linking. File photo of US Vice-President JD Vance on the phone with Donald Trump during a recent trip to Hungary JD Vance speaks on the phone with Donald Trump Chief international correspondent, in Islamabad Twenty-one hours was not enough to end 47 years of hostility between Iran and the US. The historic high-level talks in Islamabad, during a pause in weeks of grievous war, were always unlikely to end any other way. Calling this marathon negotiating session a failure belies the scale of the challenge in narrowing wide gaps on complex issues ranging from age-old suspicion about Iran's nuclear programme to new challenges this war has thrown up - most of all Iran's control of the strategic Strait of Hormuz, whose closure is causing economic shocks worldwide. To do a deal, they also needed to overcome a deep chasm of distrust. A day ago, it wasn't even certain the two sides would meet, and even more, sit down in the same room. A longstanding political taboo was broken. The urgent question now is: what happens next? What happens to the contested two-week ceasefire which pulled the world back from US President Donald Trump's alarming threat to destroy a "whole civilisation" in Iran? Would the US president be ready to send his negotiators back to the bargaining table? We're hearing reports from sources here in Islamabad that some conversations have continued after US Vice-President JD Vance boarded his plane at sunrise, declaring the US delegation had made their "final and best offer". US Vice-President JD Vance stands at a podium with Jared Kushner and Steve Witkoff behind him. Iran chose 'not to accept our terms', US VP Vance says after negotiations US Vice-President JD Vance stands at a podium next to Steve Witkoff and Jared Kushner. Vessels and a boat at the Strait of Hormuz, off the coast of Oman’s Musandam province Follow live updates on Trump's blockade threat We still don't know enough about what happened behind tightly closed doors in a five-star hotel in leafy locked-down Islamabad during talks that went on long into the night. There are still few details on the disputes and discussion between the two sides, assisted by Pakistani mediators, the calls to and from experts, advisers, and, according to Vance, "dozens" of calls to Trump himself. The vice-president spoke of the "core goal" of the US during his brief dawn news conference. "We need to see an affirmative commitment that [Iran] will not seek a nuclear weapon and they will not seek the tools that would enable them to quickly achieve a nuclear weapon," he said. During the last round of talks in February, before military strikes were unleashed again, Iran had offered new concessions including the dilution of its 440kg stockpile of uranium enriched to 60% - dangerously close to weapons-grade. But it still insists on its "right" to enrich and hasn't been willing to give up that stockpile, now said to be buried deep in the rubble after US and Israeli air strikes last year. It's also refused repeated demands to open the Strait of Hormuz - to allow the free flow of vital traffic in oil, gas and other essential goods - in the absence of a new agreement. Signs hailing the talks were taken down on Sunday after they wound up A large, blue road-side sign which reads: Islamabad Talks, April 2026. Both the US and the Iranian delegations came to Islamabad emboldened by their belief that theirs was the winning side in this war. And they engaged knowing that, if they failed, there was the option to keep fighting – whatever the spiralling pain for their own people and a world reeling from the cost of this conflagration. There was also what Dr Sanam Vakil of Chatham House describes as a "limited psychological understanding of the adversary and what compromises are needed for a real deal". Vance spoke of good news – "we've had a number of substantive negotiations" - and there was bad news: "We have not reached an agreement." And he made it clear that was "bad news for Iran much more than the United States of America". Iran's foreign ministry spokesman Esmail Baghaei criticised the US's "excessive demands and unlawful requests" in a post on X. And its parliamentary speaker Mohammad Bagher Ghalibaf, who led Iran's negotiating team, wrote that "the opposing side ultimately failed to gain the trust of the Iranian delegation in this round of negotiations". Iran is indicating it's ready to keep talking. Pakistan's Foreign Minister Ishaq Dar urged all sides to uphold the fragile ceasefire and said they would continue their efforts to encourage dialogue - sentiments being echoed in other concerned capitals. If history provides any lessons, the last time Iran reached a nuclear deal with the US and other world powers in 2015, it took 18 months of breakthroughs and breakdowns. Trump has made it clear he doesn't want to get bogged down in protracted negotiations. Vance previously warned that the US would not be receptive if Tehran tried to "play us". Pakistani journalist Kamran Yousef - in a legion of journalists who pulled all-nighters to provide non-stop coverage with very few details - declared that this round was one of "no breakthrough but no breakdown either". Do you have any views, comments or questions about this story? Please include a contact number if you are willing to speak to a BBC journalist. You can also get in touch in the following ways: Email: yourvoice@bbc.co.uk WhatsApp: +44 7756 165803 Tweet: @BBC_HaveYourSay And you can send us a video note via  WhatsApp or by  using this link .   You can also get in touch by following this link A woman sifts through the rubble in her destroyed flat in Tehran, Iran. Photo: 15 March 2026 Why did US and Israel attack Iran and how long could the war last? A woman with her child stands behind police tape next to rubble and debris on a street and looks at the aftermath of an Israeli and the U.S. strike on a police station, 2 March 2026. 'Endless fears': Even if fighting stops, the damage to Iran's children will endure A satellite image of the Strait of Hormuz with two red lines to show shipping lanes. How many ships are crossing the Strait of Hormuz? President Donald Trump launched the attack on Pope Leo after the pontiff criticised the war in Iran. UK minesweepers and anti-drone capabilities will continue operating in the region, as pressure ramps up to reopen the key shipping route. BBC Middle East Correspondent Hugo Bachega hears from people affected by this week's attacks. The failure of negotiations at the weekend has raised concerns that the global energy crisis will deepen. Top Democratic allies intensified pressure on him to exit the gubernatorial race. The conflict is now a test of wills - Iran’s capacity to absorb strikes versus Trump’s tolerance for the war's costs. It was a difficult mission, negotiating on behalf of a president whose messaging on the war has been mixed from the start. Trucking operators say their costs have doubled in a vast country reliant on the industry to deliver goods.