President Vladimir Putin announced on Wednesday he would seek re-election in March 2018, a contest opinion polls show he will win comfortably, setting the stage for him to extend his dominance of Russia's political landscape into a third decade.
The Russian leader chose an enthusiastic audience of factory workers in Nizhny Novgorod to make the announcement.
After first taking power in 2000, Putin has served three terms as president, with a four-year break when he served as prime minister in 2008-2012.
Russia's elections on March 18 are timed to coincide with the anniversary of Russia's annexation of Crimea from Ukraine-a move that boosted Putin's popularity at home.
Putin has spent a year dodging the question about whether he would run.
If he wins what would be a fourth presidential term, he will be eligible to serve another six years until 2024, when he turns 72.
"'I am sure that we will be very successful", Putin, 65, said after confirming his plan to mount a reelection bid.
Despite the Central Election Commission ruling him ineligible to stand, Navalny has organised mass protests and set up campaign headquarters across the country, hoping he can pressure the authorities into allowing him to stand.
There is no obvious successor.
Past candidates such as Communist chief Gennady Zyuganov, ultranationalist Vladimir Zhirinovsky and liberal leader Grigory Yavlinsky have all declared their intention to run. At the end of that stretch, he became prime minister to his close ally, Dmitry Medvedev - and Russian Federation then changed its law to make the presidency run for six-year terms.
That decision will be closely watched - as whoever holds that post is often seen as the president's heir apparent.
They are broadly supportive of the Kremlin's policies and have repeatedly run for president, behaviour critics say is a ruse to create the illusion of genuine political choice.
"The United Russia party that has been founded by President Putin will support his candidacy".