Russian shelling again briefly knocked out power to the Zaporizhzhia nuclear power plant, which had switched to backup diesel generators to keep critical cooling equipment running, Ukrainian nuclear officials said on Monday.

The loss of power had renewed the threat of a nuclear disaster at the plant, which is occupied by Russian troops and operated by Ukrainian engineers.

The generators have enough diesel to power the plant for 10 days.

Ukraine’s state nuclear power company, Energoatom, said on Monday morning that shelling had severed the plant’s power connection.

A few hours later, Ukraine’s state energy company said on the Telegram messaging app that it had restored external power and that the system was now running smoothly.

Rafael Mariano Grossi, the director general of the International Atomic Energy Agency, had said the outage made the situation at the plant “extremely vulnerable.”

It was the seventh time since Russia’s full-scale invasion in February 2022 that the plant had lost its connection to external electricity, Grossi said.

Each time, engineers have been able to restore power to the plant before the generators ran out of diesel, averting a possible catastrophe.

The latest blackout at the plant, which is near the front line in the partially occupied Zaporizhzhia region in southern Ukraine, started at about 5:30 a.m. on Monday,

Energoatom said. The facility lost its connection to a high-voltage power line from the nearby town of Dniprovska, the company said.

As Ukrainian forces prepare to begin an anticipated counteroffensive that could include southern Ukraine, shelling in Zaporizhzhia has increased.

Fighting in the surrounding area increases the risks to the plant, according to Grossi, who has been trying to win international backing for a demilitarized zone around the plant.

New York Times News Service