The safety around the largest nuclear power plant in Europe is a "red light blinking" following Russia's invasion, the head of the International Atomic Energy Agency (IAEA) has warned.
Rafael Grossi, director-general of the IAEA, said his organisation was struggling to get access to Zaporizhzhia plant in southern Ukraine after it was occupied by Russian troops.
His comments follow warnings from Ukraine's state-run atomic energy company on Tuesday that the war could lead to "nuclear catastrophe" after claims Russian missiles flew at low altitude over the plant.
Grossi told the Associated Press news agency that the IAEA needs access to the plant so its inspectors can make repairs sustained since Russian troops launched the invasion in February.
He also said he wants to reestablish connections with the Vienna-based headquarters of the agency.
Confirming the plant needs repairs, Grossi warned: “All of this is not happening. So the situation as I have described it, and I would repeat it today, is not sustainable as it is."
“So this is a pending issue. This is a red light blinking.”
The IAEA chief added: "Understandably, my Ukrainian counterparts do not want the IAEA inspectors to go to one of their own facilities under the authority of a third power.
"I had a long conversation about this with president Zelenskyy last night, and it’s something that will still require consultations. We are not there yet."
Grossi said he is still attempting to pressure the Kremlin into granting him and his team access, but said: "I don’t see movement in that direction as we speak."
He continued: ‘There are two units that are active, in active operation, as you know, others that are in repairs or in cool down.
"And there are some activities, technical activities and also inspection activities that need to be performed."
On Tuesday, Zelenskyy marked the 36th anniversary of the Chernobyl nuclear disaster by condemning Russia's "completely irresponsible actions" towards nuclear stations since Vladimir Putin's forces mounted an invasion on 24 February.
He spoke about the Zaporizhzhia plant in his address, in particular an attack on the area on 4 March which saw a fire break out after Russian troops began shelling.
Following the attack, the State Inspectorate for Nuclear Regulation of Ukraine reported no changes in radiation levels but warned that could change.
"They knew exactly which object they were firing at," Zelenskyy said.
"But they had an order to seize the object at any cost. They did not care about anything. They did not care that the Zaporizhzhia station was the largest in Europe.
"They didn't think about how many power units there are and how the shelling could end."
He claimed Russian troops had stolen equipment used to measure radiation, adding: “I believe that after everything that Russian troops did in the Chernobyl zone and at the Zaporizhzhia nuclear plant, no-one in the world can feel safe knowing how many nuclear sites, nuclear weapons and relevant technologies Russia has.
“If Russia forgot what Chernobyl is, it means that total control over Russian nuclear sites and technologies is required.”
On Tuesday, Ukraine's state-run atomic energy company Energoatom said cruise missiles had flown over the Zaporizhzhia nuclear power plant during an air strike on Tuesday, which local authorities said hit a commercial building in the city of Zaporizhzhia, killing at least one person.
"Missiles lying at a low altitude directly over the site of the ZNPP (Zaporizhzhia nuclear power plant), where there are seven nuclear facilities with a huge amount of nuclear material, poses huge risks," Petro Kotin, Energoatom's acting chief, said.
"After all, missiles could hit one or more nuclear facility, and this threatens a nuclear and radiation catastrophe around the world," he was quoted as saying in a statement issued by Energoatom on the Telegram messaging app.
In February, Russian troops temporarily occupied the Chernobyl plant before being ousted from the north of the country.
Ukrainian officials claimed at the beginning of April that soldiers fled the site after receiving high doses of radiation from digging into contaminated soil.
Energoatom said troops withdrew from the territory of the defunct plant after “panicking at the first sign of illness”, and had dug trenches in the highly toxic Red Forest, where the highest levels of radiation are found.