Ukraine said Wednesday that Russia's "totalitarian machine" was behind the murder of anti-Kremlin reporter Arkady Babchenko, which provoked angry denials from Moscow.
The prominent Russian war correspondent and former soldier was shot in an apparent contract on Tuesday evening -Style killing in the stairway of his building in Kiev. He moved to the Ukrainian capital last year following a harassment campaign in Moscow.
The Ukrainian police have opened a murder trial, claiming that the crime is related to his work.
"I am convinced that the Russian totalitarian machine has not forgiven him for his honesty and principled attitude," said Ukrainian Prime Minister Volodymyr Groysman on Tuesday.
"A true friend of Ukraine who told the world the truth about Russian aggression, his murderers should be punished."
Also an adviser to the Ukrainian Minister of Interior, Anton Gerashchenko, pointed to Moscow and wrote on Facebook: "The Putin regime is against those who can not break it or intimidate it."
Many politicians and observers, including Foreign Minister Pavlo Klimkin, suggested that Russia wants to sow chaos in the country already shaken by a four-year conflict with pro-Russian rebels in the East – ahead of next year's presidential and parliamentary elections.
"The leading and obvious line of research is his professional activity," said the chief of police of Kiev, Andriy Kryshchenko.
Ties between Russia and Ukraine were smashed after a popular uprising in Kyiv in 2014 overthrew a Kremlin-based president and Russia annexed the Crimea and went to support insurgents in the east of the former Soviet state.
– Three shots in his back –  Moscow denies being behind the murder.
"The Ukrainian Prime Minister is already talking about how it was done by Russian intelligence services," Foreign Minister Sergei Lavrov told reporters. "This way of leading international affairs is very sad."
Kremlin spokesman Dmitry Peskov said: "We strongly condemn this killing and hope for a real, and not a sham, who ordered it."
Investigator in Moscow opened his own probe and said that they would "not be blind to the cruel crimes against Russian citizens".
The Ukrainian police spokesman Yaroslav Trakalo said that Babchenko was found bleeding from his wife after she heard shots and that he died in an ambulance on the way to the hospital.
The journalist suffered three shots on his back.
His murder was reminiscent of the murder of several prominent Kremlin critics, including the politician Boris Nemtsov, who was shot dead near the Kremlin in 2015. Journalist Anna Politkovskaya was shot dead in the stairwell of her Moscow apartment in 2006.
In Ukraine, several have been killed in recent years, including one on a Kie One street in broad daylight and another whose car exploded.
Several countries condemned the murder of Babchenko, British Foreign Minister Boris Johnson said he was "horrified".
"We Must Defend Freedom of Speech Those responsible will now be held accountable," he said on Twitter.
The Council of Europe also condemned the "brutal act" in which Secretary-General Thorbjorn Jagland said: "It must be extensively researched and the perpetrators quickly brought to justice."
– "One Soldier's War" –
19659023] Babchenko fought in the two Chechen campaigns in the 1990s and early 2000s before becoming a war correspondent and author. He repeatedly said he was facing death threats.
He contributed to a number of media, including the leading opposition newspaper Novaya Gazeta and a zealous blogger who accused Russian authorities of killing Kremlin critics and unleashing wars in Ukraine, Syria and elsewhere  He wrote about his experiences as a young soldier in the Chechen campaigns in a book published in English under the title "One Soldier's War".
Babchenko left Russia in February 2017 after receiving threats and first lived in the Czech Republic in Israel before moving to Kiev
Last year he hosted a program on the Crimean Tatar television station ATR
Babchenko had with his poignant reports from the front lines, including the conflict in eastern Ukraine, which has killed more than 10,000 people.
In recent years, his increasingly bombastic posts have continually pushed the boundaries of good taste and some of his peers. Gues and followers stopped reading him on Facebook.
But his assassination triggered a cry of mourning among the liberal Russians.
A group of about 30 people, mostly journalists, gathered in the Russian Embassy in Kiev and hung up a picture of Babchenko
In Russia and Ukraine vigils were planned.
Russian journalist Arkady Babchenko was the last Kremlin critic living in Kiev who was killed in less than two years
People left pictures of murdered journalists Arkady Babchenko and flowers in the Russian Embassy in Kiev
The Russian journalist Arkady Babchenko was killed in the staircase of his building by three shots, a colleague said