The wife of Ukraine's military spy chief has been poisoned with heavy metals and is undergoing treatment in a hospital, a spokesperson for the agency said.
Marianna Budanova is the wife of Kyrylo Budanov, who heads Ukrainian military intelligence agency GUR.
The agency has been prominently involved in clandestine operations against Russian forces throughout the 21-month war.
"Yes, I can confirm the information, unfortunately, it is true," GUR spokesman Andriy Yusov said, without clarifying when the incident took place.
Budanov's public profile has surged in Ukraine and the West, where he is portrayed as a behind-the-scenes mastermind of efforts to strike back at Russia. In Russian media he is a hate figure.
The 37-year-old has himself been the target of several failed attempts on his life, including a botched car bombing.
If confirmed as deliberate, the alleged poisoning of his wife would represent the most serious targeting of a high-profile Ukrainian leadership figure's family member since Moscow began its invasion in February last year.
The poisoning was first reported by Ukrainian media outlets.
One publication, Babel, cited an unnamed source who said Budanova had been in hospital, and was finishing a course of treatment for the effects of the poisoning.
Ukrainska Pravda cited a source saying the poison had likely been administered in her food and that several other GUR staff members had also been poisoned.
Moscow has previously blamed Ukrainian secret services for the murders of a pro-war Russian blogger and a pro-war journalist on Russian soil. Kyiv denies involvement in those deaths.
Separately, Russian media has reported that a court in Moscow had arrested Budanov in absentia in April on terrorism charges.