A Ukrainian military intelligence colonel has been killed in a auto bomb in what is being described as a "terrorist act", it has emerged.
"National Police officers, rescuers, bomb disposal experts and criminologists are working at the scene of the incident, which has been qualified as a terrorist act".
The Defence Ministry identified the victim as Colonel Maxim Shapoval, a senior member of Ukraine's military intelligence.
The police and the ministry did not give further details or say who could be behind the attack.
Since fighting between government forces and Russia-backed separatists in eastern Ukraine broke out in April 2014, there have been a number of incidents involving explosives outside the conflict zone, though vehicle bombs are relatively rare.
In early June, a Ukrainian volunteer commander originally from the Russian region of Chechnya, who had once been jailed on suspicion of plotting to kill Russian President Vladimir Putin, was shot and seriously wounded.
Shapoval was reportedly investigating Russia's military aggression in the ongoing war in the Donbass region for Ukraine's case against Russian Federation in the International Court of Justice, also known as The Hague, Lb.ua said.
Voronenkov was fatally shot in the Ukrainian capital on March 23.
A pretrial investigation by Ukraine's Interior Ministry into Sheremet's death "led to the conclusion that this crime was carefully prepared by a group of people".
Past year high-profile independent journalist Pavel Sheremet was also killed in a auto bombing in central Kiev.
The Kremlin has denied any involvement in any of the attacks.