By Guy Faulconbridge
LONDON (Reuters) - Mikhail Khodorkovsky, a former oil tycoon who fell foul of the Kremlin, said on Monday the arrest of Kremlin critic Alexei Navalny was an attempt by President Vladimir Putin to show he is still "top dog" in Russia.
Khodorkovsky said the West should act rather than talk if it wanted to have any influence on the 68-year-old president after Navalny's arrest and that Navalny could face a decade in prison, as Khodorkovsky did after challenging the Kremlin.
Navalny was remanded in pre-trial detention for 30 days on Monday for violating the terms of a suspended jail sentence, one day after returning from Germany where he was treated for what German military tests showed was poisoning by a deadly nerve agent, a version of events rejected by the Kremlin.
The Kremlin has said Navalny must face justice like any other citizen if he has done anything wrong, and that the West should keep out of the case.
"Putin feels he has to show he is the main animal in the herd or ... people will believe that he is no longer the top dog," Khodorkovsky, 57, told Reuters in London when asked about Navalny's arrest.
"The only thing that defends Putin is the perception ... that he is the top dog - that has been placed yet again in doubt."
The Kremlin declined to comment immediately in response to Reuters' questions.
Khodorkovsky, once Russia's richest man, was arrested on a plane in Siberia in 2003 and jailed for tax evasion and fraud. His once mighty oil company, Yukos, was split apart.
The Kremlin cast him as a common criminal. Khodorkovsky denied the charges and was released in 2013 after spending 10 years in custody.
Khodorkovsky said he had to make a decision to return to Russia in 2003 even though he could face arrest.
"My situation was absolutely analogous," he said. "There was no other variant: either you surrender or you go back to fight - so Navalny did absolutely the right thing."
After Yukos was brought to its knees by vast back tax claims by the state, it was carved up and ultimately its assets were snapped up by state-run oil companies.
Khodorkovsky said the West should prioritise sanctions on individuals involved in Russian corruption abroad over sanctions on the Nord Stream 2 natural gas pipeline, which is being built between Russia and Germany and is seen in the West as a possible sanctions target.
He said he wanted to believe that Navalny would be released but he believed the reality was that he would face growing pressure from the Russian authorities.
"He could be given 10 years (in jail) - that in summary is what we could see at this stage," he said. "Much will depend on how Russian society reacts."
(Reporting by Guy Faulconbridge; editing by Michael Holden, Timothy Heritage and Jonathan Oatis)