MOSCOW, Sept 19 (Reuters) - Russians voted on Sunday in the final stretch of a three-day parliamentary election that the ruling party is expected to win emphatically after a crackdown that crushed Kremlin critic Alexei Navalny's movement and barred opponents from the ballot.
The expected win by the ruling United Russia party is likely to be used by the Kremlin as proof of support for Vladimir Putin, who has been in power as either president or prime minister since 1999.
Allies of Navalny, who is serving a jail sentence for parole violations he denies, are encouraging tactical voting against United Russia, that amounts to supporting the candidate most likely to defeat the ruling party in a given electoral district. Authorities have tried to block the initiative online.
An independent election watchdog, Golos, said it had recorded many violations during the three-day vote, including threats against observers and ballot stuffing, blatant examples of which circulated on social media, with some individuals caught on camera depositing bundles of voting slips in urns.
The Central Election Commission said it had recorded cases of ballet stuffing in six regions and that the results from those polling stations would be voided.
The Central Election Commission reported total voter turnout at 40.5% as of 1500 Moscow time (1200 GMT) on Sunday.
United Russia is facing a ratings slump due to public malaise over years of faltering living standards, state pollsters say, but it remains more popular than its closest rivals on the ballot, the Communist Party and the nationalist LDPR party, which often back the Kremlin anyway.
DOMINANCE
United Russia holds nearly three quarters of the outgoing State Duma's 450 seats. That dominance last year helped the Kremlin pass constitutional reforms that allow Putin to run for two more terms as president after 2024, potentially staying in power until 2036.
"If United Russia manages (to win), our country can expect another five years of poverty, five years of repression, five lost years," ran a message to supporters on Navalny's blog.
Navalny's allies were barred from running after his movement was banned in June as extremist. Other opposition figures allege they were targeted with dirty tricks campaigns.
A Communist strawberry tycoon says he was unfairly barred, while a liberal opposition politician in St Petersburg says two identically-named "spoiler" candidates are running against him to confuse his voters.
The Kremlin denies a politically-driven crackdown and says individuals are prosecuted for breaking the law. Both it and United Russia deny any role in the registration process for candidates.
Since voting began on Friday, Google, Apple and Telegram messenger have limited some access to the tactical voting campaign, leading activists to accuse them of caving to pressure from the government. Apple and Google have not responded to the allegation.
"One day we will live in a Russia where it will be possible to vote for good candidates with different political platforms," Navalny ally Leonid Volkov wrote on Telegram messenger.
"And Navalny's party will vye for a seat in parliament in fair and competitive elections. But for now, 'smart voting' is voting for Navalny."
The election runs until 1800 GMT on Sunday when polling stations close in the European exclave of Kaliningrad. It is the last national vote before the 2024 presidential election. Putin, who turns 69 next month, has not said whether he will run again.
One Moscow pensioner who gave his name only as Anatoly said he voted United Russia because he was proud of Russia's muscular foreign policy and Putin's efforts to restore what he sees as Russia's rightful great power status.
"Countries like the United States and Britain more or less respect us now like they respected the Soviet Union in the 1960s and 70s… The Anglo-Saxons only understand the language of force," he said.
Other voters voiced anger at United Russia at a polling station in the capital of more than 12.5 million, where the party has fared worse in recent years than in other regions.
"I'm always against United Russia," said Roman Malakhov, who voted Communist. "They haven't done anything good."