REUTERS

"I will participate in the fight for the post of president of Russia," Navalny said in a videotaped statement posted on a new campaign website on December 13, RFE/RL wrote.

The decision potentially sets up Navalny, a fierce critic of President Vladimir Putin, to challenge the longtime leader in a direct election.

Putin is eligible to seek a new six-year term in the election and is widely expected to do so, but has not announced his candidacy.

Read alsoThe Moscow Times: Russian journalist Shlosberg to receive first Nemtsov prize"Russia should be a rich, free, strong country.… I am going into the election with a program to make Russia strong and modern. To curb corruption. To turn Russia's riches into prosperity for every family," Navalny said on the website. "A presidential election is a discussion about the country's path of development."

Navalny was a key leader of major antigovernment protests in 2011-12 and has harried Putin with a series of reports alleging corruption among high-level Russian officials.

He has been convicted of financial crimes twice in trials he says were Kremlin-dictated revenge for his opposition activities, but the Supreme Court in November threw out the verdict in one of the cases and sent it back for a new trial, removing a legal restraint that had barred him from running for office.

If he is convicted in the retrial now under way, he would likely be prohibited from running in 2018.