Former oligarch and prominent Kremlin critic Mikhail Khodorkovsky on Monday called on Western governments not to recognise Vladimir Putin's election win, affirming that the opposition was united against the Russian ruler.
"It is now about... finally publicly recognising Putin as illegitimate," Khodorkovsky told journalists in Berlin.
"We have high expectations for Western society, who we ask to turn to their governments to ask them not to recognise Putin as legitimate," he said in an event at the Center for Liberal Modernity think tank.
"When Western heads of state and government shake Putin's hand, that is a very strong legitimation for Putin at home."
Former oil tycoon Khodorkovsky spent a decade in prison after challenging Putin early in his rule and has financed Kremlin-critical projects from exile.
Based in London, Khodorkovsky met Yulia Navalnaya, the widow of dissident Alexei Navalny, on Sunday as she voted in the Russian presidential elections in Berlin.
The pair held discussions outside the Russian embassy, where thousands of people lined up to cast their ballots in a sign of protest.
The opposition mobilisation from noon Sunday was organised in memory of Navalny, and saw huge crowds gather at polling stations abroad and in Russia.
Opposition figures including Navalnaya were agreed on the "key questions", Khodorkovsky said, dismissing talk of divisions.
"We no longer want Putin in power and we want to create clarity with honest, transparent elections," he said.
Sunday's election results had "nothing to do with reality", Irina Scherbakova, co-founder of the Nobel Peace Prize-winning Russian rights organisation Memorial, told AFP in Berlin.
Putin's 87-percent share of the vote showed "the rise of this dictatorship," Scherbakova said.
The apparent landslide was a "very threatening symbol", she said, warning of "hard times" ahead for the domestic opposition in Russia.
"We have to expect that violence and repression will be used and that Putin will want revenge."
The election had however shown that there were "many people who are not afraid to actually express their opinion", she said.