In a statement on its website today, his Other Russia coalition blames the Central Election Commission and "administrative pressure" for making it impossible to notify authorities of the venue for his official nomination, a step that was required five days before the last day for registration on December 17.
"Left with no legal means to announce his candidacy, Garry Kasparov has opted to rescind his name from the roster," Other Russia announces. "As an act of protest, and to demonstrate his support, the leader of the Other Russia coalition will continue campaigning unofficially. He has already begun collecting signatures from around the country, and is raising grassroots support."
It quotes Kasparov as saying that "it is impossibly [sic] to play fairly under the Kremlin's rules."
Speaking at the funeral on December 13 of an opposition activist in Serpukhov, south of Moscow, Kasparov had said, "We understand a decision has been made not to allow my registration even at this preliminary stage."
On December 12, Kasparov declared that he would drop his presidential ambitions if the following day's deadline could not be met, saying government pressure prevented Other Russia from meeting requirements to get his name on the ballot.
"It is now technically impossible," his spokesman Denis Bilunov told AFP on December 13.
The conference scheduled to nominate Kasparov -- at which at least 500 supporters were required to be present -- had to be canceled on December 12 because, he said, no venue was available in all of Moscow. The cancellation came a day before the deadline for candidates' "initiative groups" to inform the Central Election Committee of their intention to hold a nominating conference.
Kasparov spokeswoman Marina Litvinovich told RFE/RL's Russian Service that the government appeared to be pressuring venues not to rent conference space to Kasparov's supporters.
"Judging from the situation yesterday evening, as well as this morning (December 13), we still don't have any space in Moscow which we could rent for money and have a gathering of our group," Litvinovich said. "Therefore, it can be said that we have been unable to execute this very first step, necessary for launching a campaign for the Russian presidential elections."
The authorities have denied the accusation. Election Committee official Aleksei Kisin told Interfax that "there are a lot of buildings, in Russia in general and in Moscow in particular, where people can gather for very different reasons."
Even if Kasparov had managed to beat the deadline, he had virtually no chance of victory in the March 2 vote. It almost certain that President Vladimir Putin's stated preference as his successor, Dmitry Medvedev, will win easily.
Kasparov's announcement was followed by other reports of harassment of people and groups with ties to his party, United Civil Front. The former chess champion's wife and daughter were reportedly detained for a document check as they tried to board an international flight on December 12, causing them to miss the flight.
Kasparov and supporters of the Other Russia umbrella group, which includes Kasparov's party, ran into trouble on December 13 as they traveled to a Serpukhov to attend the funeral of Yuri Chervochkin, who died from injuries sustained during an antigovernment rally in November. The 22-year-old activist was allegedly beaten by police.
Litvinovich told RFE/RL's Russian Service that two busloads of opposition supporters were held up for 45 minutes by a half dozen riot policemen at a checkpoint on the road to Serpukhov, where the funeral was held.