Security Service of Ukraine (SBU) officials found weapons and Russian cash on Wednesday after searching properties in around Kyiv linked to a pro-Russian former politician, the agency said.
In a statement, the SBU said its searches of homes and offices belonging to Yevhen Murayev, who it said was "hiding from justice abroad", and his associates were part of a criminal investigation into treason.
Murayev's political party and a television channel under his control were seen as vehicles for Kremlin interests in Ukraine before Moscow's Feb. 24 invasion. The party, Nashi, was banned after Russian forces swept into Ukraine.
He had promoted views that aligned with Russian narratives on Ukraine, including that the 2014 Maidan protests in Kyiv were a Western-backed coup and the Kremlin-fuelled war in eastern Ukraine that followed was an internal conflict.
Weeks before Russia's full-scale attack on Ukraine this year, Britain's foreign ministry said Russia was considering installing Murayev to lead a new puppet government, a claim denied both by him and by Moscow.
The SBU said an independent analysis of Murayev's public statements "testify to the presence in his actions of signs" of treason.
It said the materials seized in Wednesday's searches would be examined further.
(Reporting by Dan Peleschuk; Editing by Mark Heinrich)
