Russia's presidential campaign is officially under way.
The campaign began on December 18, in line with a formal resolution by the upper parliament last week scheduling the election for March 18.
Candidates now 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.
President Vladimir Putin announced on December 6 that he will 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 will run as an independent candidate rather than being nominated by the Kremlin-controlled United Russia party.
Kremlin critics have said that March 18 -- the anniversary of the day in 2014 on which Putin signed a treaty that Moscow claims made Ukraine's Crimean Peninsula part of Russia -- was chosen to promote the incumbent.
His popularity rose after the occupation and takeover, which most countries say was illegal but is celebrated in Moscow as Crimea’s "reunification with Russia."
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 independent Russian agency Levada Center 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.