KIEV/MOSCOW: A dissident Russian journalist who was reported murdered in Kiev dramatically reappeared alive on Wednesday in the middle of a briefing about his own killing by the Ukrainian state security service.

Ukrainian authorities had said on Tuesday that Babchenko, a 41-year-old critic of President Vladimir Putin and of Russian policy in Ukraine and Syria, had been shot dead at his flat and that his wife had found him in a pool of blood.

His reported murder had triggered a war of words between Ukraine and Russia and sent shivers through the journalistic communities in both countries.

But on Wednesday, an emotional Babchenko appeared before reporters saying he had been part of a special Ukrainian operation to thwart a Russian attempt on his life and said he was fine.

"I would like to apologise for what you have all had to go through," Babchenko, who looked on the verge of tears at times, told reporters.

"I'm sorry, but there was no other way of doing it. Separately, I want to apologise to my wife for the Hell that she has been through."

He went on to thank the Ukrainian Security Service, the SBU, for saving his life and said the most important thing was that what he called other big acts of terror had been thwarted. He did not specify what those planned acts were.

The SBU said it had received information about the plot and had managed to prevent it.

Babchenko, a Putin critic, lived in the Ukrainian capital after receiving threats at home for saying he did not mourn the victims of a Russian military plane crash.

Ukrainian Prime Minister Volodymyr Groysman said in a social media posting late on Tuesday he was convinced what he called "the Russian totalitarian machine" had not forgiven Babchenko for what Groysman called his honesty.

The Kremlin described such allegations as part of an anti-Russian smear campaign.

"This is the height of cynicism against the backdrop of such a brutal murder. It is anti-Russian bluster instead of talking about the need to conduct a thorough, objective investigation," Kremlin spokesman Dmitry Peskov told reporters before it was revealed that Babchenko was alive and well.

Babchenko sparked a backlash in Russia for his comments in a 2016 Facebook post on a Russian military plane crash. He said his comments had resulted in thousands of threats, his home address being published online and calls for him to be deported.

The plane, carrying 92 people, including dozens of Red Army Choir singers, dancers and orchestra members, crashed into the Black Sea on its way to Syria in December 2016, killing everyone on board.