ISLAMABAD, April 12 (Xinhua) -- No agreement was reached between the United States and Iran in the latest round of talks held in Islamabad, U.S. Vice President JD Vance said here on Sunday, as negotiations concluded without a breakthrough despite intensive engagement.

Vance said the U.S. side had presented its "final and best offer" after nearly a day of continuous communication, adding that a number of substantive discussions were conducted in "good faith," but the proposal had yet to secure acceptance.

He said Iran's nuclear enrichment facilities have been "destroyed," shifting the focus of negotiations to securing a long-term commitment from Tehran not to develop nuclear weapons.

The U.S. vice president said the key question now is whether Iran is willing to demonstrate sustained intent to refrain from pursuing nuclear capabilities, not only in the immediate term but in the years ahead.

"The simple fact is that 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," Vance said. "That is the core goal of the president of the United States and that's what we've been trying to achieve through these negotiations."

Iran's semi-official Tasnim news agency also reported on Sunday that negotiations between Iran and the United States in Islamabad have concluded without an outcome, as the U.S. "excessive demands" hindered a common framework and agreement.

Earlier in the day, Iranian Foreign Ministry spokesman Esmaeil Baghaei said on X that in the past 24 hours, discussions with the United States were held on various dimensions of the main negotiation topics, including the Strait of Hormuz, the nuclear issue, war reparations, lifting of sanctions, and the complete end to the war against Iran and in the region.

He said that the success of this diplomatic process depends on the seriousness and good faith of the opposing side, refraining from excessive demands and unlawful requests, and the acceptance of Iran's legitimate rights and interests.

The high-stakes talks were reported to be the highest-level meeting between the United States and Iran since 1979.

Vance also thanked Pakistan for its efforts to help the United States and Iran bridge the gap and get to a deal. Before the talks, the U.S. and Iranian delegations met with Pakistani Prime Minister Shehbaz Sharif separately, who expressed the hope that these talks would serve as a stepping stone toward durable peace in the region.