A prominent pro-Russian Ukrainian journalist was shot dead on Thursday by two masked gunmen, further heightening tensions between Moscow and Kiev.
Buzina was shot in the street, Ukraine's interior ministry said in a statement.
He wrote for Segodnya a daily newspaper that is owned by prominent Ukrainian businessman Rinat Akhmetov, Reuters reported. Akhmetov was close to Ukraine's Pro-Russia ex-president Viktor Yanukovych.
Buzina was the second pro-Russian public figure killed in the country this week, and the latest of many Russian supporters who have died under suspicious circumstances in recent months.
On Wednesday, former parliamentary official Oleh Kalashnikov was also killed while heading to his apartment, Reuters reported.
At least four others have died in recent months in apparent suicides or in mysterious ways, according to Reuters.
The deaths have caused tensions to flame between Russia and Ukraine, with Russian President Vladimir Putin claiming the deaths are politically motivated.
Ukrainian President Petro Poroshenko ordered the deaths be investigated thoroughly and with transparency.
He said the deaths "play into the hands of our enemies."
Max Seddon contributed to this article.