“The election results testify to support shown by citizens of Russia for policies consistently implemented by the country’s political leadership,” Pashinian said in a congratulatory message publicized by his office.
He expressed confidence that “close cooperation” between the newly elected State Duma, the lower house of Russia’s parliament, and Armenia’s National Assembly will help to “advance the Russian-Armenian alliance.”
With 99.7 percent of ballots counted, the Russian Central Election Commission said United Russia, which backs Putin, won 49.84 percent of the vote. Its closest rival, the Communist Party, had 18.95 percent, and the nationalist Liberal Democratic Party received 7.5 percent.
United Russia Secretary-General Andrei Turchak said the party expects to control 315 of the Duma's 450 seats, giving it a comfortable two-thirds majority that continues to allow it to change the constitution.
The three-day elections were marred by allegations of voting irregularities and ballot tampering.
An independent monitoring agency called them "one of the dirtiest" elections in Russian history.
Germany said on Monday that the allegations must be taken “seriously and should be clarified” and the European Union denounced the climate of "intimidation" in the run up to the vote.
The vote is widely seen as an important part of Putin’s efforts to cement his grip on power ahead of a possible run in the 2024 presidential election, making control of the State Duma key.