Shells hit a high-voltage power line at the Zaporizhzhia plant, prompting operators to disconnect a reactor despite no radioactive leak being detected.

The plant was captured by Russian forces back in March, but is still run by Ukrainian technicians.

Ukrainian President Volodymyr Zelenskyy has accused Moscow of committing "an open, brazen crime" and "an act of terror" - and is calling for fresh sanctions on the entire Russian nuclear industry.

In a late night address, he said: "It is a purely a security issue. Those who create nuclear threats to other nations are certainly not capable of using nuclear technologies safely."

Ukraine's foreign ministry warned: "The possible consequences of hitting an operating reactor are equivalent to the use of an atomic bomb."

Meanwhile, Russia's defence ministry claimed Ukraine's armed forces were to blame, and said it is a matter of luck that a radiation leak was avoided.

It said in a statement: "Fortunately, the Ukrainian shells did not hit the oil and fuel facility and the oxygen plant nearby, thus avoiding a larger fire and a possible radiation accident."

Energoatom - Ukraine's state nuclear power company - says the Zaporizhzhia plant remains operational and no radioactive discharges have been detected.

Earlier this week, the UN's nuclear watchdog appealed for access to the plant, with Washington claiming that Russia is using the site as a battlefield shield.

More grain shipments leave Ukraine

In other developments, three more ships carrying thousands of tonnes of corn left Ukrainian ports on Friday.

It is another sign that a deal to export grain trapped since Russia invaded the country almost six months ago is slowly moving forward.

Subscribe to Ukraine War Diaries on Apple Podcasts, Google Podcasts, Spotify and Spreaker

But hurdles lie ahead to get food to the countries that need it the most, and experts claim most of the supplies Ukraine is trying to export will be used for animal feed.

The shipments are not expected to have a meaningful impact on the global price of corn, wheat and soybeans.