Ukraine's security services said Sunday they had discovered a bug in one of the offices used by army chief Valery Zaluzhny, but added that it was "not operational".
The report comes as Ukraine is fighting to maintain western support for its war against Russian forces after its recent counter-offensive failed to make major headway in the east and the south of the country.
"We emphasize that the equipment was found not directly in Valery Zaluzhny's office, but in one of the premises that could be used by him for work in the future," said the statement.
"According to preliminary data, the found device was in a non-operational state," it added.
"No data storage devices or means of remote audio transmission were found. This technical device will be sent for examination."
Both Ukrainian and foreign news media have reported on what they say is growing tension in recent months between Zaluzhny, Ukraine's top general, and Ukraine President Volodymyr Zelensky.
Zaluzhny said last month the conflict with Russia had ground to a "stalemate" -- an assessment rejected by both President Volodymyr Zelensky and the Kremlin in Moscow.
Ukraine's army has been battling the invading Russia force since February 2022.