BERLIN (AP) -- An external power line to Ukraine's Zaporizhzhia nuclear power plant -- the biggest in Europe -- was repaired on Sunday after shelling disconnected the facility from the grid and forced it to resort to emergency diesel generators, the U.N. nuclear watchdog said.
The International Atomic Energy Agency said the 750-kilovolt line was reconnected to the plant on Sunday evening following repair work by Ukrainian engineers. That enabled the plant to start switching off the generators that had kicked in to provide it with power after the line -- its last connection to the grid -- was cut early Saturday.
IAEA Director-General Rafael Grossi tweeted that the reconnection was "a temporary relief in a still-untenable situation."
The plant has been held by Russian forces for months, but operated by Ukrainian employees. All six reactors at the site are shut down but they still require electricity for cooling and other safety functions.
Grossi has spent weeks pushing for the establishment of a "nuclear safety and security protection zone" around the plant. He says he will travel to Russia and then see Ukrainian President Volodymyr Zelenskyy in an effort to realize that plan.
Grossi condemned attacks "in areas that could affect the safety and security" of the plant, including in nearby Enerhodar and in the Ukrainian-held provincial capital of 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," he said. "The shelling must stop, immediately. It is already having an impact on the nuclear safety and security situation at the plant."
Ukrainian operating staff told IAEA experts that a convoy of five trucks carrying "vital additional diesel fuel supplies" is currently in the city of Zaporizhzhia and plans to cross the front line to reach the plant on Monday, the agency said. The site currently has diesel reserves for about 10 days. Separately, a supply of diesel provided by the Russian state nuclear company Rosatom has arrived in Enerhodar, the IAEA added.
Zaporizhzhia is one of four regions in Ukraine that Russian President Vladimir Putin has annexed in violation of international laws.
Putin signed a decree Wednesday declaring that Russia was taking over the nuclear plant. Ukraine's Foreign Ministry called it a criminal act and said it considered Putin's decree "null and void." Ukraine's state nuclear operator, Energoatom, said it would continue to operate the plant.