Russia's top election official says that opposition politician Aleksei Navalny will not be eligible to run for office until about 2028.
Speaking at a youth festival in the southern city of Sochi, Central Election Commission chief Ella Pamfilova warned Navalny and his backers against arguing that he can seek the presidency in a March 2018 vote.
Navalny, 41, has campaigned actively ahead of the election, in which President Vladimir Putin is widely expected to seek and secure a fourth term in the Kremlin.
But the CEC said in June that he is ineligible to run for public office because of a financial-crimes conviction in one of two high-profile cases that he says were fabricated by authorities for political reasons.
"Mr. Navalny is a young politician with a future. He has every chance," state-run news agency TASS quoted Pamfilova as saying.
Due to the conviction, however, he cannot run for office until "sometime in about 2028 plus six months," she said.
Navalny has organized protests in cities nationwide on several occasions in recent months, including on Putin's 65th birthday on October 7.
Ralliers called on the authorities to let Navalny run in the election, scheduled for March 18, and hundreds were detained by police.
Pamfilova accused allies of Navalny of misinterpreting the law and "brainwashing" young people.
She said that when Navalny's "so-called lawyers try to put false information into kids' heads," saying that he has the right to run, "that is a lie."
If Putin serves another term starting in 2018, he would be constitutionally barred from running in the subsequent election in 2024.
The next presidential election after that is due to be held in 2030.
In addition to organizing street protests, Navalny has rattled the Kremlin by publishing reports alleging high-level corruption among allies of Putin.