Iran’s supreme leader has denounced a proposal by the United States aimed at curbing Tehran’s nuclear efforts and demanded that his country retains national independence amid reports of Washington offering to become involved in Tehran’s nuclear program.

Iran's supreme leader on Wednesday criticized an initial proposal from the United States in negotiations over Tehran's rapidly advancing nuclear program, though he stopped short of entirely rejecting the idea of agreement with Washington.

The future of high-stakes negotiations over Iran's nuclear program remains shrouded in uncertainty as the U.S. and Iran publicly clash over the terms of an interim agreement proposed by the Trump administration that is intended to pave the way for a longer-lasting deal.