The SBU has interrogated MP Viktor Medvedchuk as part of an investigation into the high treason case, a law enforcement source told Interfax-Ukraine.

"Medvedchuk was interrogated on Tuesday by SBU investigators in criminal proceedings," the agency's interlocutor said.

The source did not specify what kind of criminal proceedings were in question, noting only that, most likely, the interrogation was carried out as part of investigation of the high treason case, which investigates the facts of recently published conversations between Medvedchuk and former assistant to the President of Russia Vladyslav Surkov.

"At the same time on Tuesday, the fifth president of Ukraine, Petro Poroshenko, was summoned to the SBU investigators, but he did not arrive," the agency's interlocutor said.

As reported, on February 2, President of Ukraine Volodymyr Zelensky put into effect the NSDC decision, which effectively blocked the activities of three TV channels - 112.Ukraine, Newsone and ZIK, which are associated with one of the leaders of the Opposition Platform party Viktor Medvedchuk.

Later, in one of the online publications, a recording was made public of the alleged conversation between the former assistant to the President of Russia Vladyslav Surkov and Viktor Medvedchuk, who in 2014 discussed the supply of electricity to the occupied Crimea and the exchange of prisoners in Donbas.

Then the SBU press center reported: "These records are carefully studied by the investigative and operational units of the SBU regarding the presence of signs of a criminal offense in the actions of the interlocutors."