Russia's presidential campaign is due to kick off on December 18 after the date of the election -- March 18 -- was officially set.
The date was made official by a vote in the Federation Council, the upper parliament chamber, on December 15.
President Vladimir Putin announced last week that he would seek a new six-year term. His high approval ratings and control over the levers of power virtually ensure that he will win.
On December 14, Putin told reporters he would run as an independent candidate rather than being nominated by the Kremlin-controlled United Russia party.
After December 18, candidates have 20 days to submit their registration documents to the Central Election Commission.
Independent candidates must collect at least 300,000 signatures in support of their bid, while candidates from parties not represented in the parliament must collect at least 100,000 signatures.
Central Election Commission chief Ella Pamfilova said on December 15 that at least 23 people have expressed their intention to run for president.
The election commission has said that opposition leader and anticorruption activist Aleksei Navalny, a fierce critic of Putin, is ineligible to run due to a financial-crimes conviction he contends was politically motivated.
Other declared candidates include Communist Party leader Gennady Zyuganov, nationalist Vladimir Zhirinovsky, liberal Grigory Yavlinsky, business ombudsman Boris Titov, and journalist and TV personality Ksenia Sobchak.
Opinion poll results released by the Levada Center, an independent Russian agency, on December 13 put support for Putin at 61 percent, followed by 8 percent for Zhirinovsky, 6 percent for Zyuganov, and 1 percent or less for the others.
With reporting by TASS, Interfax, and AP