"[Babchenko] showed up at Gritsak's news conference on Wednesday and thanked everyone who was mourning his death", AP reported.
"I am sorry, but there were no options here", Babchenko said at the presser.
Gritsak said investigators had identified a Ukrainian man who had been recruited and paid $40,000 (£30,000) by Russian security services to organise and carry out the killing.
He has contributed to a number of media outlets including top opposition newspaper Novaya Gazeta and is an avid blogger, accusing Russian authorities of killing Kremlin critics and unleashing wars in Ukraine, Syria and elsewhere.
A badly bleeding Babchenko was supposedly found by his wife at the entrance to their apartment building on Tuesday. At the news conference in Kiev, Babchenko had an important apology to make.
Mr Babchenko, 41, is one of Russia's best-known war reporters, but was forced to leave the country past year because of repeated threats against him and his family. The Russian ministry said that Ukraine "deceived the entire global community" with the ruse, which was now clearly exposed as a publicity stunt meant to smear Russia.
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Venezuela has since expelled a USA diplomat based in the capital Caracas for allegedly "conspiring" against the government. ". Until Trump's tweet on Saturday, the US had stopped short of publicly calling Holt a " hostage ".
The murder "was ordered by Russia's security forces", Hrytsak said on Wednesday (Thursday NZ Time).
Groysman added that Babchenko was "a true friend of Ukraine", due to his commitment to reveal "the truth about Russian aggression".
Writing past year in The Guardian, Babchenko described how a Facebook post he had written about the Russian bombing of civilians in Aleppo, Syria, was deemed insufficiently patriotic and led to a systematic campaign against him.
The Investigative Committee of Russian Federation said it had opened a criminal case into Mr Babchenko's death.
Babchenko left Russian Federation in February 2017 after receiving threats, living first in the Czech Republic, then in Israel, before moving to Kiev.
Russian Foreign Minister Sergei Lavrov said Ukraine's accusations were "very sad" as an investigation into the incident had yet to begin.
He claimed this Facebook post, in which he described Russia as an "aggressor", led to death threats and abuse from the Russian state.
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