Iran’s Supreme Leader Ayatollah Ali Khamenei said he does not expect negotiations with the United States over Tehran’s nuclear program to “reach a conclusion” as Washington toughens its conditions for a deal.

Iran’s supreme leader has pushed back against U.S. criticism of the country’s nuclear program. Ayatollah Ali Khamenei said Tuesday that Tehran won’t seek permission from anyone to enrich uranium and called American statements “nonsense.

Ayatollah Ali Khamenei has lashed out at the U.S. president, accusing him of lying about his intentions to use American power for peace.