A nuclear facility in Iran was hit by a terrorist act a day after it unveiled new advanced uranium centrifuges, a top nuclear official says.
He did not say who was to blame but urged the international community to deal with nuclear terrorism.
Israeli media suggest the incident was a result of an Israeli cyber-attack.
Last year, a fire broke out at the Natanz underground facility, which the authorities alleged was the result of cyber sabotage.
The latest incident comes as diplomatic efforts to revive a 2015 nuclear deal – abandoned by the US under the Trump administration in 2018 – have resumed.