Media captionBack from the dead?
"We are relieved that #ArkadyBabchenko is alive, Ukrainian authorities must disclose what necessitated the extreme measure of staging news of the Russian journalist's murder", the group wrote on Twitter.
The Belgian Foreign Ministry qualified the faked murder as an attempt to fight deceit with the help of lies and stressed that Ukraine's actions contradicted the principles of the spread of information accepted in Europe. "The hybrid war waged by the Russian Federation against Ukraine demands unorthodox approaches while effecting countermeasures", Ukraine's embassy in London said.
With police announcing his death, it appeared as if the assassination had been completed, and Mr Babchenko said: "The person paid money for a completed crime". Moscow said it was a provocation. He then startled everyone there by inviting the 41-year-old reporter into the room.
German Foreign Minister Heiko Maas said ahead of a visit to Kiev on Thursday that it is "indispensable to shed light on what happened" and called on Ukraine to clarify the situation in order to "encourage trust".
Ukrainian police have arrested one man, who works for a Ukrainian-German arms producing company.
Relations between Kiev and Moscow have been tense since Moscow annexed Crimea in 2014 and was accused of covertly backing rebels in the bloody conflict in eastern Ukraine.
Some wondered if the ruse would ultimately backfire, harming Ukraine's credibility or undermining concern about violence against journalists.
"I'm still alive", an uneasy-looking Babchenko said with a straight face. "It is the duty of the state to provide correct information to the public".
"As a direct outcome of these actions, obviously created to attain a certain propaganda effect, the entire global community, which quickly responded to the reports of a media representative from Ukraine, was, in fact, misled", the foreign ministry said.
How did the story develop?
Authorities said Arkady Babchenko was shot dead at his flat and found by his wife in a pool of blood.
Babchenko's reappearance was reportedly greeted with gasps and applause from journalists assembled at the press conference in Kiev.
"There was no other way", he said.
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.
Poroshenko welcomed Babchenko with a hug at the presidential administration and said the journalist and his family would be given protection. "It is unlikely that Moscow will calm down", he added.
Gritsak, the security service chief, ended his remarks Wednesday congratulating Babchenko on his "third birthday".
The 2016 military plane crash had 92 people on board, including 60 members of the Red Army Choir. From the morgue, where he changed clothes, Mr Babchenko watched television reports on his death until he was taken to a safe house.
Babchenko said he is staying in a secure location for the time being and his immediate plans are to try to overcome the stress he's endured. The Ukrainian government still hasn't arrested or prosecuted anyone for Sheremet's assassination, but investigative journalists discovered that an agent of the SBU, Ukraine's security service, had been sitting outside Sheremet's building the night the bomb was planted on his vehicle.