Former member of the State Duma of the Russian Federation has given evidence to Ukrainian investigators in the criminal proceedings into high treason by ex-president of Ukraine Viktor Yanukovych, Ukraine's Prosecutor General Yuriy Lutsenko has said.

"I can confirm [Prosecutor of Main Military Prosecutor's Office] Ruslan Kravchenko's words that one of the witnesses who gave very important testimony is a former deputy of the Russian State Duma. He testified about the impact of the letter signed [by Yanukovych] with an appeal to Putin to bring troops to Ukraine on the decision of the State Duma to sanction the use of Russian armed forces abroad," Lutsenko told reporters in Kramatorsk on Tuesday.

According to him, these statements will form the basis for future charges.

As reported, Yanukovych is suspected under two articles of the Criminal Code - Articles 110, 111 (high treason and violation of the territorial integrity of the state).