Ukraine's security service said on Sunday it had launched a criminal probe under a law on information gathering after a "technical device" was found in an office that could have been used in the future by Commander in Chief Valery Zaluzhnyi.
The security service said on the Telegram messaging app that an investigation had been opened under an article in Ukraine's criminal code on "unlawful acquisition, sale, or use of special technical means for obtaining information".
It added that the device -- initially characterized as a bug by local media -- was considered under preliminary information to be "in a non-operational state", and no means of information storage or remote transmission of audio recordings were found.
"We emphasise that the device was found not directly in Valery Zaluzhnyi's office but in one of the premises that could have been used by him in the future for work," the service said.
"The Security Service of Ukraine is taking all legally prescribed measures to investigate this offence," it added.
Zaluzhnyi has been mentioned among possible targets for a reshuffle in top military ranks under a cooling in relations with President Volodymyr Zelenskiy, who has disagreed with his view of the conduct of the 21-month-old war against Russia.
In an essay published last month in The Economist, Zaluzhnyi wrote that the war was entering a stage of attrition that could benefit Moscow and allow it to rebuild its military power.
The president has disagreed with any notion the war was subject to a stalemate.
