Sochi mayoral candidate Boris Nemtsov criticized a decision by election officials to allow people from Abkhazia with Sochi residency permits to vote in Sunday's election.

This decision is "unprecedented even for Putin's Russia" and the Abkhaz vote will effectively "join the republic to the city," Nemtsov wrote on his Internet blog Thursday.

The Sochi election committee ruled this week that thousands of Abkhaz people with Russian citizenship and Sochi residency permits could participate in the election, which is favored to be won by acting Mayor Anatoly Pakhomov, United Russia's candidate. The decision is upheld by election law.

Nemtsov said the ruling would further tarnish the legitimacy of the vote and could lead to an international scandal. Russia has issued passports to most residents of the breakaway Georgian region of Abkhazia, which Moscow recognized as independent last year. No other country except Nicaragua has recognized the separatist republic as independent.