Iran's Supreme Leader Ayatollah Ali Khamenei said on Wednesday that abandoning uranium enrichment was "100%" against the country's interests, rejecting a central U.S. demand in talks to resolve a decades-long dispute over Tehran's nuclear ambitions.

An outline by the Trump administration would allow Iran to continue enriching uranium at low levels while a broader arrangement is worked out that would block the country’s path to a nuclear weapon.

Iran's stance directly clashes with U.S. President Donald Trump 's position that Iran must halt all enrichment amid negotiations marked by uncertainty, despite having reached their most significant step since they began in April with a U.S. offer being delivered to Tehran last week.