An aide to Ukrainian Prime Minister Volodymyr Hroysman has been detained on suspicion of being an agent of Russia's Federal Security Service (FSB).
A government representative to parliament, Vadym Denysenko, told 112 Ukrayina TV on December 21 that Stanislav Yezhov was detained a day earlier.
Media reports say that Yezhov accompanied Hroysman on his international trips and often served as an interpreter.
He has worked in the past in the president's office and at the Ukrainian Embassy to the United States.
On December 20, the Ukrainian Security Service (SBU) announced that it had apprehended a government employee, whose identity was not disclosed, on suspicion of "acting in the interests of security services of the aggressor country."
The detainee was officially informed that he is a suspect, the SBU said.