Russia and Ukraine accuse each other of shelling the facility, with heavy fighting raging around Europe's largest nuclear plant.
Russia accused Ukraine of taking Europe hostage by shelling the Zaporizhzhia plant, while Ukraine's President Volodymyr Zelenskyy said Russia is creating the threat of a nuclear disaster. Experts have warned that continued fighting around the site is fraught with danger.
What is happening at the Zaporizhzhia nuclear plant in Ukraine?
In March, the site was seized by Russian forces, but Ukraine is currently staging a counter-attack in the area.
Ukrainian technicians are still working at the plant under Russian occupation.
Russia said Ukrainian shelling caused a fire and power surge on Monday, while Ukraine blamed Russia for weekend attacks, which left three radiation sensors damaged and two workers injured.
Petro Kotin, head of Ukraine's state nuclear power company, Energoatom, said the plant appears to still be running.
He warned that Ukrainian staff at the plant have nowhere to stay.
500 Russian soldiers and 50 vehicles, including tanks, trucks and armoured vehicles, are at the site, according to Kotin.
Where is the plant of Zaporizhzhia? The facility, which has six reactors, is situated near the Dnieper River in Enerhodar, south-west of the city of Zaporizhzhia, about 800 kilometres south of Ukraine's capital Kyiv.
The site has Europe's largest nuclear reactor complex, built during the Soviet era, and its total output is enough to power 4 million homes.
It occupies a key strategic position in southern Ukraine, with both sides fighting for control of the region.
A reactor building was damaged during fighting around the site in March.
Could there be a nuclear accident in Ukraine?
Any attack on a nuclear plant suicidal United Nations chief Antonio Guterres has demanded UN nuclear inspectors be given access to the site.
Zaporizhzhia's reactors are reinforced with steel and concrete and designed to withstand an impact from a commercial airliner.
The disruption of the plant's normal safety regime is a danger, experts say, with Ukrainian technicians working under stressful and difficult conditions.
Their reactors need constant cooling, even though nuclear plants can be shut down. Any disruption to the cooling pump's electricity supply could create risks.
There are concerns over the site's spent nuclear fuel storage areas, with reports of rocket strikes nearby.
He described the situation as completely out of control. The 1986 Chernobyl meltdown was caused by a chain of events that caused a major explosion and fire and the release of a plume of radioactive material across Europe.
The fighting, the size of the plant and the harsh rhetoric from Russia and Ukraine are causing concern.
Nuclear expert Mark Weiman, from Imperial College London, said that the spent fuel storage areas are strong and probably don't contain much spent fuel despite reports of missile strikes.
What is done to bring things under control in Zaporizhzhia?
There is a lot of words but little action so far.
The UN and the IAEA have called for international experts to be allowed in, and Ukraine has called for the site to be recognised as a demilitarised zone.
There seems to be little chance that Russia will agree to this, given its strategic value.
Russia has accused Ukrainians of blocking a visit by IAEA experts.
Russia's RIA Novosti news agency quoted Moscow's ambassador to the IAEA as saying Russia is ready to facilitate a visit to the reactor complex.