A presidential bid by former Soviet dissident Vladimir Bukovsky ended on Saturday when the Russian Central Election Commission ruled his candidacy invalid, bringing the number of contenders to six.
Bukovsky, a British resident, was told he could not run in the March 2 election to replace President Vladimir Putin because the consitution requires candidates to have spent at least 10 years living in Russia, RIA Novosti news agency reported.
The commission also said it was barring Bukovsky because he held dual citizenship, Interfax news agency reported.
Putin's handpicked successor Dmitry Medvedev was registered this week as the candidate of the ruling United Russia party and is expected to win the race without difficulty.
Also registered are Communist Party leader Gennady Zyuganov, and ultra-nationalist LDPR party leader Vladimir Zhirinovsky.
There are three independent candidates: former Kremlin insiders Mikhail Kasyanov and Boris Nemtsov, and the leader of the tiny Democratic Party. They each still face the task of collecting two million signatures from supporters before they are officially registered.