They fired the head of "Ukrenergo" - the electricity transmission network of Ukraine, reports "Reuters".
Volodymyr Kudrytsky was released with 4 votes "for" against 2 votes "against" by the Supervisory Board of the company on grounds of inability to protect energy facilities.
He will be replaced in the post by Alexii Brecht.
The decision follows a meeting last week between President Volodymyr Zelensky and senior military officials on the spate of Russian attacks on energy targets. It was also attended by the Minister of Energy Herman Halushchenko.
Ahead of the board meeting, Ukrainian media published a letter from Western organizations active in Ukraine, including the European Union, expressing "deep concern" to Prime Minister Denis Schmigal regarding the reports of Kudritsky's impending dismissal.
"Such an event could jeopardize our collective ability to support "Ukrenergo" and other priority measures for Ukraine's vital energy security," the letter states.
Yaroslav Zhelezniak, an opposition member of parliament, predicted that the international reaction would be "quick and quite painful".
Ukrainian media suggest that the main reason for the dismissal was the company's inability to provide adequate protection for energy sites and irregularities in the awarding of contracts.
Newspaper "Economic Justice" cited anonymous government sources as saying that Kudritsky, who has been the head of the company since 2020, has not followed through on decisions made at previous meetings of the military command.
In two and a half years of war, Russia has committed significant resources to attack and disable key Ukrainian energy targets. Over the past week, Moscow's forces launched a new wave of attacks.