Russia's ruling party appears to have lost multiple seats in Moscow's city legislature, according to preliminary voting results reported by state news agency RIA-Novosti.

Self-nominated candidates aligned with United Russia, which supports President Vladimir Putin, are set to occupy 26 of 45 seats in the Moscow City Duma, RIA-Novosti cited Valentin Gorbunov, head of the Moscow Election Commission, as saying.

United Russia previously held 28 seats, along with 10 self-nominated candidates backed by the party.

Gorbunov said the Communist Party won 13 seats, and the Just Russia party and the liberal Yabloko party won three seats each, RIA-Novosti reported. The total turnout of eligible voters was 21.8%, said the agency.

Russian opposition leader Alexey Navalny claimed a tactical victory in the elections, saying that United Russia had suffered a major setback.

“It's clear that (the) Smart Voting (political strategy) worked,” Navalny wrote. “Throughout the history of the MGD (Duma), the party in power has not lost so many districts. All well done. However, it's too early to relax.”

Independent and opposition candidates were largely kept off the ballot by local authorities, prompting activists to call for several weeks of street protest. Navalny urged the “Smart Voting” strategy, encouraging voters to cast ballots for candidates likely to unseat United Russia.

Moscow Mayor Sergei Sobyanin said in a statement on Twitter that Sunday's vote was “perhaps the most emotional and really competitive in all of recent history. On average, almost five candidates fought for mandates in each constituency. Passions were serious.”

Sobyanin acknowledged the change in the city parliament.

“In addition to a strong detachment of Communists, a cohort of respected parties Yabloko and Just Russia will take seats in parliament,” he said. “The Duma has become politically more diverse, which in general, I hope, will benefit the city parliament.”