Mr. Babchenko, 41, was scathing in his criticism of Kremlin policies, assailing Moscow’s annexation of Crimea, its support of separatist insurgents in eastern Ukraine and its military campaign in Syria.
He left Russia in February 2017, saying he was receiving threats and was concerned he might be jailed. He moved to Kiev last fall, where he worked as a host for the Crimean Tatar television station, ATR.
Anton Gerashchenko, a Ukrainian lawmaker who serves as an adviser to the interior minister, said Mr. Babchenko’s killer had been waiting for him in the staircase inside his building and shot him in the back as he was going out.
Another well-known journalist, Pavel Sheremet, a native of Belarus who had worked for Russian news media outlets, was killed in a car bombing in Kiev in July 2016. The case remains unsolved.
Mr. Babchenko had served in the Russian Army and fought during the first separatist war in Chechnya during the 1990s. He later became a military correspondent for several Russian news media outlets, and published several books on his wartime experiences.