"Unreasonable demands" by the United States scuppered talks in Islamabad to end the war in the Middle East, Iranian state broadcaster IRIB has said.
"The Iranian delegation negotiated continuously and intensively for 21 hours in order to protect the national interests of the Iranian people; despite various initiatives from the Iranian delegation, the unreasonable demands of the American side prevented the progress of the negotiations," IRIB said on Telegram.
"Thus the negotiations ended."
Iran’s Fars news agency, citing sources, said that the US was looking for an excuse to leave the negotiating table.
Iran’s Press TV reported that discussions concluded because the US's excessive demands prevented a framework from being reached.
Earlier, US Vice President JD Vance announced that Iran and the US failed to reach an agreement to end the war in the Middle East, after marathon talks in Islamabad, adding that he was leaving negotiations after giving Tehran the "final and best offer".
Vance said Washington was seeking a "fundamental commitment" from Iran that it would not develop a nuclear weapon, but that "we haven't seen that" after holding the highest-level meeting between the two sides since the 1979 Islamic revolution.
However, he signalled that he was still giving time to Iran to consider the offer from the United States, which on Tuesday said it would pause attacks with Israel for two weeks pending negotiations.
The United States and Israel had attacked Iran in February 28, sparking retaliation from Tehran that has plunged the Middle East into conflict and the global economy into tumult.
Iran and the US had entered the talks mediated by Pakistan with maximalist positions, with Washington also piling pressure by saying it had sent minesweeping ships through the vital Strait of Hormuz.
Signs of strain in the negotiations appeared when Iranian media accused the United States of making "excessive demands" on the Strait of Hormuz, through which one-fifth of the world's oil transits.
Meanwhile, Vance was departing Pakistan on Sunday, according to a pool report, soon after saying that talks with Iran failed to reach an agreement.
Vance boarded Air Force Two at 7:08 am (0208 GMT) and waved to Pakistani officials from the top of the stairs.
