Ukraine’s Prime Minister Volodymyr Groysman has accused Russia of being behind the killing in Kiev of the Russian journalist Arkady Babchenko.
“I am confident that the Russian totalitarian machine did not forgive him his honesty and principled stance,” the prime minister posted on Facebook.
A Kremlin critic, Babchenko was gunned down outside his apartment on Tuesday.
Russia has called for an investigation but said “bloody crimes” had become routine for the “Kiev regime”.
Babchenko, 41, was found bleeding at the entrance to his block of flats by his wife and died in an ambulance.
He was reportedly shot several times in the back.
Ukrainian lawmaker Anton Herashchenko said the journalist had gone out to buy some bread, and that the killer was waiting for him.
Kiev police chief Andriy Kryshchenko told local media they suspected Babchenko was killed because of his “professional activities”.
Relations between Russia and Ukraine remain tense following Russia’s annexation of Crimea in 2014 and the seizure of parts of eastern Ukraine by pro-Russian forces.