"Yes, he [the killer] has died," director of the ministry's media liaison office Artem Shevchenko said.

Another source in the Ukrainian interior ministry said that he was identified as a Ukrainian citizen.

Read alsoRussia's former MP compares RF with Nazi Germany, calls occupation of Crimea blunderUkraine's Prosecutor General Yuriy Lutsenko earlier said at a briefing in Kyiv on Thursday afternoon that the assassin had two wounds – to the chest area and an exit wound to his head.

Voronenkov's wounded security guard is alive and is cooperating with the investigators, he said.

The guard was shot in the heart area, but he is alive and conscious and he is cooperating with the investigators, Lutsenko added.