Ayatollah Ali Khamenei
Ayatollah Ali KhameneiReuters

Iranian Supreme Leader Ayatollah Ali Khamenei threatened Monday to enrich uranium to even higher levels if the US does not remove sanctions on the Islamic Republic, vowing to "not back down on the nuclear issue."

Khamenei threatened that Iran would enrich uranium to 60%, further shortening the breakout time to a nuclear bomb.

In January, Iran began enriching uranium to 20% in violation of the 2015 nuclear deal which capped Iran's enrichment levels at 3.67%. There is no civilian use for enriching uranium to 20%. Uranium must be enriched to 90% to develop a nuclear weapon.

"Iran's enrichment limit will not be 20%, and we will act to the point that is needed and the country requires," Khamenei said. "The Islamic republic will not back down on the nuclear issue and will strongly continue down the path of what the country requires for today and tomorrow."