Khamenei said, during a meeting with commanders of the US terrorist-designated Iranian Revolutionary Guards Corps (IRGC): “We will continue the reduction of commitments. The responsibility is with the Atomic Energy Organization and they must be carried out the reduction …in a precise, complete and comprehensive way and continue until the time we reach the desired result.”
The nuclear deal was agreed by the P5+1 countries (Britain, France, Germany, China, Russia, and the United States) and Iran after months of negotiations. The idea was that Iran would scale back its nuclear program in exchange for sanctions relief.
However, there is little evidence to suggest that Iran has ever complied with these restrictions in the first place. The US withdrew from the deal last year citing Iranian noncompliance and shortly after that Iranian officials began admitting that they’d never properly dismantled the main centrifuge. Add to that, the fact that Iran had twice been caught going over the limit for the amount of enriched uranium they could stockpile and you understand why the US pulled out.
In addition, Iran continually tested ballistic missiles capable of carrying nuclear weapons, which was a violation of the United Nations resolution enshrining the nuclear deal. (Iran has always claimed that the resolution merely “calls upon” them not to test these missiles, using a technicality to avoid action by the UN.)
In May of 2019, Iran announced that they would stop complying with the nuclear deal altogether unless the European signatories helped the Regime evade US sanctions.
Of course, Europe had already done a lot in that regard, but they can’t force European companies to do business with Iran, even when that means being cut off from the bigger US market.
Thus, Iran began to openly violate the nuclear deal. First, they again went over the 300-kilogram limit of enriched uranium that they were allowed to stockpile. Then, they began to increase the purity of the enriched uranium above 3.67%, even threatening to go to 20% purity.