Iran's Supreme Leader Ayatollah Ali Khamenei said on Wednesday Tehran will not abandon its uranium enrichment, rejecting a key U.S. demand aimed at resolving a decades-long nuclear dispute, that he said was against the Islamic Republic’s interests.

On Monday, an Iranian diplomat told Reuters Tehran was poised to reject a US proposal to end a decades-old nuclear dispute, dismissing it as a "non-starter" that fails to soften Washington's stance on uranium enrichment or to address Tehran's interests.

Iran’s Supreme Leader Ayatollah Ali Khamenei on Wednesday slammed a preliminary proposal from the United States in talks about Tehran’s nuclear program.