US vice-president JD Vance left Islamabad on Sunday after failing to reach a deal with Iran after a marathon 21 hours of negotiations.Vance cited shortcomings in the talks, saying that Iran had chosen not to accept American terms, including to not build nuclear weapons.

“The bad news is that we have not reached an agreement, and I think that’s bad news for Iran much more than it’s bad news for the United States of America,” Vance said.

“So we go back to the United States having not come to an agreement. We’ve made very clear what our red lines are.”

Vance said he spoke with US president Donald Trump at least half a dozen times during the talks, and one of the most significant points of difference between the two sides had been around the development of nuclear weapons.

“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, “That is the core goal of the president of the United States, and that’s what we’ve tried to achieve through these negotiations.”