Putin foe Navalny expects to be jailed for many more years

Russian opposition politician Alexei Navalny expects a court to extend his prison sentence by nearly two decades on Friday, in a criminal case that he and his supporters say was trumped up to keep him behind bars and out of politics for even longer.

Navalny, 47, President Vladimir Putin's fiercest domestic critic, is already serving sentences totalling 11-1/2 years on fraud and other charges that he says are also bogus. His political movement has been outlawed and declared "extremist".

State prosecutors have asked the court to hand him another 20 years in a penal colony on six separate criminal charges, including inciting and financing extremist activity and creating an extremist organisation.

In a message posted on social media on Thursday, Navalny said the outcome could be slightly less, around 18 years, but it didn't really matter because he was also threatened with terrorism charges that could bring another decade.

"It's going to be a long sentence," said Navalny, who is able to post on social media via his supporters and lawyers.

He said the purpose would be to frighten Russians, but urged them not to let that happen and to think hard about how best to resist what he called the "villains and thieves in the Kremlin".

The charges relate to his role in his now defunct movement inside Russia, which the authorities said had been trying to foment a revolution by seeking to destabilise the socio-political situation.