Ukrainian Communist Party leader Petro Symonenko has been summoned by the Ukrainian Security Service (SBU) for questioning over a recent trip to Russia.
SBU spokeswoman Olena Hitlyanska said on April 1 that Symonenko will be questioned about the visit in which he reportedly took part in a Russian Communist Party meeting.
She said the SBU was also investigating comments Symonenko made on Russian television that could be seen as calling for crimes to be committed "against the foundations of Ukraine's national security."
"There is every reason to open a criminal case and to investigate facts that may provide evidence of complicity of the [Communist Party's] top leadership in illegal activities," Hitlyanska added.
The SBU expects Symonenko to appear for questioning on April 2.
Symonenko appeared on Ukrainian television channel 112 on April 1 and said he was in Ukraine but knew nothing about being summoned by the SBU.
He said he had not done anything illegal while in Russia.