Iran said it had passed 4.5% enrichment, breaching the 3.67% limit set in the accord aimed at restraining Tehran's nuclear weapons development.
Iran said it could consider enriching uranium to 20% as the next step in its move to back away from its commitments under the nuclear deal, unless it gets the help it wants from the accord's other signatories to overcome the crippling effect of U.S. economic sanctions imposed by U.S. President Donald Trump after he withdrew from the pact last year.
Uranium enriched to 5% is sufficient to produce fuel for nuclear power plants, but still far below the 90% needed for building a nuclear weapon.
The United Nations atomic watchdog agency said it was in the process of verifying the Iranian claim that it had breached the enrichment limit.
The European Union, one of the signatories to the deal with Iran, said it was "extremely concerned" about Tehran's action.
Russia said it is concerned about the Iranian action, but Kremlin spokesman Dmitry Peskov said it had warned that Trump's withdrawal from the pact would have negative consequences for global security.
Trump warned Iran on Sunday it "better be careful."
He did not specify to reporters any specific reactions his administration was considering, but reiterated the position that "Iran will never have a nuclear weapon."
Source : VOA