ISLAMABAD (AP) — The United States and Iran ended face-to-face talks on Sunday without an agreement, leaving a fragile two-week ceasefire in doubt.

U.S. officials said the negotiations collapsed over what they described as Iran’s refusal to commit to abandoning a path to a nuclear weapon, while Iranian officials blamed the U.S. for the breakdown of the talks without specifying the sticking points.

Neither side indicated what will happen after the 14-day ceasefire expires on April 22. Pakistani mediators urged all parties to maintain it. Both said their positions were clear and put the onus on the other side, underscoring how little the gap had narrowed throughout the talks.

“We need to see an affirmative commitment that they will not seek a nuclear weapon, and they will not seek the tools that would enable them to quickly achieve a nuclear weapon,” Vice President JD Vance said after the 21-hour-long talks.

Iran’s parliament speaker Mohammad Bagher Qalibaf, who led Iran in the negotiations, said it was time for the United States “to decide whether it can gain our trust or not.”