Moscow Mayor Sergei Sobyanin says he plans to resign in order to run in an early election for the post.
Sobyanin said on June 4 that an election could be held in September.
Sobyanin was confirmed as Moscow mayor for five years in 2010 but a law regulating regional elections was amended last year allowing for mayors to be elected by direct vote.
Sobyanin said, "an elected mayor can defend their [Moscow residents'] interests more effectively because he will have the political support of Muscovites."
Elections had been set to take place in 2015.
Russian media reports say calling an early election gives Sobyanin an advantage over his rivals as it would give them only two months to prepare their campaigns.
Anticorruption blogger Aleksei Navalny said on June 4 he was also planning to run for mayor.
Based on reporting by RIA Novosti, ITAR-TASS, and Interfax