Vice President JD Vance said negotiations between the United States and Iran ended early Sunday without a deal after the Iranians refused to accept U.S. terms to not develop a nuclear weapon.

The high-stakes talks in Pakistan ended after 21 hours, Vance said, with the vice president in constant communication with President Donald Trump and others in the administration.

“But 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 told reporters.

The war that has killed thousands of people and shaken global markets entered its seventh week.

The U.S. delegation led by Vance and the Iranian delegation led by parliament Speaker Mohammad Bagher Qalibaf had discussed how to advance a ceasefire already threatened by deep disagreements and Israel’s continued attacks against the Iranian-backed Hezbollah in Lebanon.