Vladimir Putin's top critic Alexei Navalny will only be able to run for president after 2028, the head of the Russian Central Election Commission said on Tuesday.
In a separate announcement, Europe's top rights court ruled Navalny's 2014 conviction for fraud was "arbitrary and unreasonable" and ordered Russia to pay him and his jailed brother 83,000 euros ($98,000) in damages and costs.
Russians are scheduled to go to polls to elect a president next March and Navalny, 41, has declared his intention to stand against Putin.
Navalny has long said the multiple court cases against him were politically motivated and designed to sabotage his presidential ambitions.
In the 2014 trial, Navalny received a suspended three-and-a-half-year sentence while his brother Oleg was sent to prison in a case related to their work for French cosmetics company Yves Rocher.
In February 2017, a court found Navalny guilty of embezzlement in connection with a timber firm and handed him a five-year suspended sentence. Officials say the ruling makes him ineligible to stand for president.
The case dates back to 2013 and a retrial came after the European Court of Human Rights (ECHR) said the first trial was unfair.
Ella Pamfilova, the head of the Central Election Commission, said Navalny would be able to put his name on the ballot once his criminal record has been expunged -- "after 2028."
Speaking at a forum in the Black Sea resort of Sochi, Pamfilova said Navalny would be able to run in just over 10 years.
"He's got his whole life ahead of him," she was quoted as saying by Russian news agencies.
"So he should proceed from that. And good luck to him!" she added, calling him a "young, promising politician."
On the same day, the ECHR ruled that the Russian courts had inappropriately applied commercial law in order to convict Navalny and his younger brother in the Yves Rocher case.
Last year, the European court declared his 2013 conviction for alleged embezzlement of funds from the regional Kirov government was also unfair.
Navalny's lawyer said she would lodge a demand with Russia's top court to close the case against him following the European ruling.
"The most important thing for us is that the ECHR acknowledged that article seven of the Convention for the Protection of Human Rights and Fundamental Freedoms had been broken which happens extremely rarely," Olga Mikhailova told the Interfax news agency.
"According to the decision, the Navalny brothers were convicted illegally, in that the act for which they were tried was not a criminal offence."
His defence team would "ask the Russian Supreme Court not just to review but to terminate the case," she said.
Russia's justice ministry said it disagreed with the ECHR ruling and would consider appealing.
Putin, 65, was first elected president in 2000 and is widely expected to seek another six-year Kremlin term in the March election.
In early October, a court sentenced Navalny to 20 days in jail for repeatedly violating a law on organising public meetings, the third such sentence he has served this year.
He is due to be released on Sunday and has said he will appear at a pre-election rally the same evening.
In 2013, the charismatic Yale-educated lawyer stood for Moscow mayor with a Western-style campaign and a message of snuffing out corruption, coming second against a Kremlin-backed incumbent.