The head of the U.N.’s nuclear watchdog said Wednesday that a Ukrainian nuclear plant surrounded by Russian troops has lost all external power needed for vital safety systems for the second time in five days.

International Atomic Energy Agency Director-General Rafael Grossi said agency monitors at the Zaporizhzhia Nuclear Power Plant reported the interruption and said backup diesel generators are keeping nuclear safety and security equipment operational.

“This repeated loss of #ZNPP’s off-site power is a deeply worrying development and it underlines the urgent need for a nuclear safety & security protection zone around the site,” Grossi tweeted.

THIS IS A BREAKING NEWS UPDATE. AP’s earlier story follows belowUkrainian forces recaptured five settlements in the southern Kherson region, according to the southern Operational Command.

The villages of Novovasylivka, Novohryhorivka, Nova Kamianka, Tryfonivka and Chervone in the Beryslav district were retaken as of Oct. 11, according to the speaker of the southern command Vladislav Nazarov.

The settlements are in one of the four regions recently annexed by Russia.

Meanwhile, Russia’s top domestic security agency said Wednesday it arrested eight people on charges of involvement in the bombing of the main bridge linking Russia to Crimea, while an official in the southern Ukrainian city of Zaporizhzhia said Russian forces carried out more strikes there.