Ukrainian President Poroshenko said that the Russian opposition leader Boris Nemtsov was going to disclose evidence of the involvement of Russian troops in the military actions in Ukraine.

"A few weeks ago I talked to him [Nemtsov] on how to build relations between Ukraine and Russia in the way we would like them be. Boris declared that he intended to make public conclusive strong proof of the participation of Russian armed forces in Ukraine. Someone was very afraid of this. Boris wasn't afraid, and the executioners were afraid. They killed him," the president said in Vinnytsia on Saturday.

According to Poroshenko, Boris Nemtsov was a great friend of Ukraine, Russian patriot, who was like a bridge connecting two states. He was building the most desirable for Ukrainians relations between Ukraine and Russia.

"On March 1, he supposed to lead a many thousand meeting to demonstrate that there is another Russian who loves Ukraine, respects human rights, for which freedom is not an empty phrase. And for the sake of freedom and democracy, he was ready to sacrifice his life," said Poroshenko.

Nemtsov was killed on Saturday night in Moscow downtown.