Ukraine has issued iodine tablets to civilians near the Zaporizhzhia nuclear power plant amid fears of a radiation leak due to the constant shelling. 

Oleksandr Starukh, the governor of Zaporizhzhia region, instructed residents within a 30-mile radius how to use potassium iodide on Ukrainian television. 

The pills are 'being distributed in case of any future radiation leak', the governor said.

Around 25,000 tablets have been delivered to the city of Enerhodar from the regional reserve.

Potassium iodide helps block the absorption of radioactive iodine by the thyroid gland in the event of a nuclear catastrophe.

One dose should give protection for 24 hours.

The Zaporizhzhia plant, which has six of Ukraine's reactors, has been occupied by Russian troops since shortly after Moscow launched its invasion on February 24, and has remained on the frontlines ever since. 

Radiation levels in the region are currently normal but Ukraine and Russia have accused each other of shelling the plant, risking a leak.

Ukraine's state nuclear company Energoatom said Kremlin forces shelled the grounds again in the past 24 hours and they are still assessing the damage.

Some shells even fell near units storing reactor fuel and radioactive waste. 

Energoatom said: 'There are risks of hydrogen leakage and sputtering of radioactive substances, and the fire hazard is high.'

But the Kremlin said Ukrainian shells had struck the roof above '168 assemblies of nuclear fuel of the Westinghouse firm'.

Under the barrage of shelling last week, the facility was already temporarily knocked offline. 

International Atomic Energy Agency chief Rafael Grossi said today he was on his way to Zaporizhzhia to assess the site.

'The day has come, IAEA's Support and Assistance Mission to Zaporizhzhia is now on its way,' Grossi tweeted, saying the team from the UN atomic watchdog would arrive at Europe's largest nuclear power plant 'later this week'.

In a photograph accompanying his tweet, the IAEA chief posed with a team of 13 people wearing caps and sleeveless jackets bearing the nuclear watchdog's logo.

Grossi has for months been asking to be able to visit the site, warning of 'the very real risk of a nuclear disaster'.

The United Nations has called for an end to all military activity in the area surrounding the complex.

Ukraine initially feared an IAEA visit would legitimise the Russian occupation of the site before finally supporting the idea of a mission. 

Zelensky on Friday urged the watchdog to send a team as soon as possible.