Vienna: Ukrainian engineers restored external power to the Zaporizhzhia Nuclear Power Plant (ZNPP) today, a day after the facility lost the connection to its last remaining operating power line due to shelling, Director General Rafael Mariano Grossi of the International Atomic Energy Agency (IAEA) said on Monday.

After the repair work was successfully completed, the 750 kilovolt (kV) line was reconnected to Europe's largest nuclear power plant in the evening, enabling it to start switching off the emergency diesel generators that had provided it with back-up electricity since the connection was cut early on Saturday.

In a statement, IAEA said the plant's six reactors are in cold shutdown but still require power for cooling and other essential nuclear safety and security functions.

Director General Grossi, who received news about the restored off-site power from the team of IAEA nuclear safety, security and safeguards experts present at the plant site, said it was a much-needed development but that the power situation at the ZNPP remained fragile.

Also today, the Director General condemned military attacks in areas that could affect the safety and security of ZNPP, including in the cities of Enerhodar and Zaporizhzhia.

"Almost every day now, there is shelling in the region where the Zaporizhzhia Nuclear Power Plant is located and where the plant workers and their families live. The shelling must stop, immediately. It is already having an impact on the nuclear safety and security situation at the plant," he said.

In recent days, there has been frequent shelling in an industrial area between the ZNPP and Enerhodar. There have also been missile strikes further away, including the tragic one on Sunday in the city of Zaporizhzhia.

A convoy of five trucks carrying vital additional diesel fuel supplies for the ZNPP is currently in the city, planning to cross the frontline to reach the plant tomorrow, senior Ukrainian operating staff told the IAEA experts at the site, the UN agency said. The site's current diesel reserves last for about 10 days.

"These military attacks in Zaporizhzhia and its vicinity increase the risk of a nuclear accident, if they hit the plant's external power lines or make it more difficult to deliver vital supplies of fuel and equipment," Director General Grossi said.

The Director General has proposed the establishment of a nuclear safety and security protection zone around the ZNPP, engaging in high-level talks with Ukraine and the Russian Federation aimed at agreeing and implementing such a zone as soon as possible.

Further highlighting the potential risks to the plant, a landmine exploded in the afternoon today outside its perimeter fence, the team of IAEA experts were informed at the site, the latest in a series of such blasts over the past few weeks.

Separately, a supply of diesel fuel provided by the Russian state nuclear company ROSATOM has arrived in Enerhodar.