Iran’s sole nuclear power plant has undergone an unexplained temporary emergency shutdown, the country’s state TV reported.
An official from the state electric company Tavanir, Gholamali Rakhshanimehr, said on a talk show broadcast on Sunday that the Bushehr plant shutdown began on Saturday and would last “for three to four days”.
Without elaborating, he said that power cuts could ensue.
It is the first time Iran has reported an emergency shutdown of the plant, which is in the southern port city of Bushehr.
The plant went online in 2011 with help from Moscow.
Under a nuclear non-proliferation measure, Iran is required to send spent fuel rods from the reactor back to Russia.
Earlier in the day, Tavanir released a statement saying the Bushehr plant was being repaired and that the work would take until Friday.
In March, nuclear official Mahmoud Jafari said the plant might stop working because Iran cannot procure parts and equipment for it from Russia owing to banking sanctions imposed by the US in 2018.
Bushehr is fuelled by uranium produced in Russia, not Iran, and is monitored by the UN’s International Atomic Energy Agency. The IAEA acknowledged being aware of reports about the plant, but declined to comment.
Construction of the plant, on the coast of the northern reaches of the Arabian Gulf, began under Iran’s Shah Mohammad Reza Pahlavi in the mid-1970s. After the 1979 Islamic Revolution, it was damaged repeatedly in the Iran-Iraq war. Russia later completed the work.
The plant sits near active fault lines and has been periodically shaken by earthquakes, but it was built to withstand them.
No significant earthquakes have been reported in the area in recent days.
Meanwhile, diplomats said progress had been made at talks in Vienna on Sunday between Iran and global powers to restore the 2015 agreement to contain Iranian nuclear development that was abandoned by the Trump administration.
They said it was now up to the governments involved in the negotiations to make political decisions.
The EU chaired the final meeting in the sixth round of talks between Russia, China, Germany, France, Britain and Iran.
The nations involved in the negotiations have been trying to resolve major outstanding disagreements over how the US can rejoin the landmark nuclear agreement, from which president Donald Trump withdrew Washington unilaterally in 2018.
Mr Trump also restored and augmented sanctions to try to force Tehran to renegotiate the pact to win more concessions.
The meeting was the first since Iran’s hard-line judiciary chief won a landslide victory in the country’s presidential election last Friday.
Some diplomats expressed concern that the election of Ebrahim Raisi could complicate a possible return to the nuclear agreement.