A team from the UN's nuclear watchdog is finally on its way to Europe's largest nuclear power plant, which has been occupied by Russian forces since February.
Rafael Grossi said the mission from the International Atomic Energy Agency (IAEA) should arrive at Zaporizhzhia later this week.
On Monday, Ukraine's foreign minister Dmytro Kouleba said the mission would be the "toughest in the history of the IAEA".
Ukraine alleges Russia is essentially holding the plant hostage, storing weapons there and launching attacks from around it.
Moscow accuses Ukraine of recklessly firing on the facility.
It has sparked global concerns of a nuclear disaster. Last week, Ukraine president Volodymyr Zelenskyy warned Europe was "one step away" from a radiation disaster.
The IAEA tweeted its mission will assess physical damage to the facility “determine functionality of safety and security systems” and evaluate staff conditions, among other things.
Ukraine’s atomic energy agency has painted an ominous picture of the threat by issuing a map forecasting where radiation could spread from the Zaporizhzhia plant. And on Monday, it accused Russian forces of continuing to shell the wider area.
Energoatom said in a statement that over the past 24 hours, Russian troops targeted the nearby city of Enerhodar and the power plant, wounding 10 people, four of whom worked at the plant.
Attacks were also reported over the weekend both in Russian-controlled territory adjacent to the plant along the left bank of the Dnieper River and along the Ukraine-controlled right bank, including the cities of Nikopol and Marhanets, each about 10 kilometres from the facility.
Russian Defense Ministry spokesman Igor Konashenkov said on Sunday that Ukrainian forces had attacked the plant twice over the past day and that shells fell near buildings storing reactor fuel and radioactive waste.
“One projectile fell in the area of the sixth power unit, and the other five in front of the sixth unit pumping station, which provides cooling for this reactor,” Konashenkov said, adding that radiation levels were normal. It was not possible to independently verify the accusations.
The IAEA reported Sunday that radiation levels were normal, that two of the Zaporizhzhia plant’s six reactors were operating and that while no complete assessment had yet been made, recent fighting had damaged a water pipeline, which has since been repaired.