Jailed Russian opposition leader Alexei Navalny said on Wednesday that investigators had opened what he called an “absurd” terrorism case against him that could see him sentenced to an additional 30 years in jail, writes Reuters.

Navalny, a former lawyer who rose to prominence more than a decade ago by lampooning President Vladimir Putin’s elite and alleging large-scale corruption, is serving combined sentences of 11-1/2 years for fraud and contempt of court on charges that he says were trumped up to silence him.

He appeared in a Moscow court via video link on Wednesday as part of a case into extremism, Reuters reporters at the court said.

“They have made absurd accusations, according to which I face 30 years in prison. I insist that the attempt to close the process is an attempt not just to prevent me from getting acquainted with the case, but it is also an attempt to make sure that no one finds out about it”, - he said in a statement published on social media by his supporters.

Navalny added it was absurd to argue he had committed terrorism while in prison. He said the case would be tried by a military court.