Former Ukrainian SBU Security Service chief Valentyn Nalyvaichenko has said he is convinced disgraced ex-Ukrainin President Viktor Yanukovych surrendered Crimea and Ukraine knowingly and deliberately to Russia.

"He surrendered Crimea and Ukraine knowingly. Russia did not even have to pressure him," he said during hearings in Kyiv's Obolonsky District Court in the state treason case against Yanukovych on Wednesday.

Nalyvaichenko said close ties between the special services of Ukraine and Russia were restored after Yanukovych became president in 2010 laid the ground work for Russia's invasion in Ukraine.

The ex-SBU chief said he had given prosecutors information showing the arrival in Ukraine during late 2013 and early 2014 three groups of high-ranking Russian Federal Security Service agents.

On February 22, 2014, following the Revolution of Dignity, Nalyvaichenko was appointed acting SBU chief, a position he kept until June 2015.

Nalyvaichenko also headed the SBU from December 2006 through March 2010.