Police said they had made one arrest.
The national police said Babchenko, 41, who fled Russian Federation a year ago, was shot a number of times in his back and was found by his wife.
The security service declined to say who the other 29 people were.
"Olechka, I am sorry, but there were no options here", Babchenko said during the press conference. Babchenko wrote that while he felt no joy over the passenger's deaths, he also felt no sympathy for those killed because they were pawns of Russian state operations.
Authorities had received information about a Russian security services plot to kill Babchenko and managed to prevent it.
He added that a Ukrainian citizen had been recruited and paid $40,000 (£30,130). It's not even certain that it's Babchenko in the photo.More news: Body of missing Guardsman found in flood-ravaged Maryland
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On Wednesday Russian foreign ministry spokeswoman Maria Zakharova said the affair was a propaganda exercise by Ukraine, but that she was happy Babchenko was alive.
"Let it always happen", she said.
The Ukrainian President Petro Poroshenko announced that his country would be offering Babchenko protection. Moscow is unlikely to calm down - so I ordered protection to be given to Arkady and his family.
He described his experience in the Chechen conflicts - which saw Moscow suppress a separatist insurgency in the North Caucasus - in a book published in English under the title "One Soldier's War".
Kremlin critic Arkady Babchenko has been seen in Ukraine. He left Russian Federation past year after receiving death threats and being denounced by pro-Kremlin politicians over his criticism of the Syrian and Ukrainian wars.
In December 2016, Babchenko wrote a Facebook post (in Russian) about a crashed Tu-154 transport plane, which went into the Black Sea while carrying a Red Army choir to Syria.
The journalist left Russian Federation in February 2017 after he claimed he had been receiving threats and shared concerns he might be jailed.
He was extremely critical of Russia's annexation, and was forced to flee the country in February 2017 because of threats to him and his family. But how it came to light and circulated in the hours after the fake killing was reported is a key element of a law enforcement sting that enlisted a former journalist, a Ukrainian lawmaker, and possibly many others.