CNN  — 

Russia saw protests at polling stations on Sunday on the final day of voting in an election set to extend Russian President Vladmir Putin’s long hold on power.

Lines at some polling stations in Russia grew suddenly at around 12pm local time Sunday, the hour at which supporters of the deceased opposition leader Alexey Navalny called on people to turn out collectively as a show of opposition support.

A CNN team at a polling station in Moscow said the line grew rapidly over a five- to ten-minute spell at around noon, and estimated 150 people had arrived.

The CNN team said that police were letting people in batches through the gates to pass through security, with metal detectors and bags being checked inside the building.

One 39-year old voter said he had come at noon “to see other people, and they have come too.”

A woman told the CNN team, “This is the first time in my life I have ever seen a queue for elections.” Asked why she had come at that hour, she simply replied: “You know why. I think everybody in this queue knows why.”

Voters queue at a polling station in St. Petersburg, Russia, at noon local time on Sunday.

It’s unclear how many polling stations across the country saw an increase in people waiting at around noon. The Reuters and AFP news agencies also reported protests taking place.

Social media channels set up by supporters of Navalny showed video clips of lines in several places, including Moscow neighborhoods such as Nekrasovka and at Tverskaya Street and locations in St Petersburg. The Navalny team also posted an image from the city of Novosibirsk with the caption: “Today is #noon. The protest has already taken place in the first cities of Siberia. We are looking forward to seeing you.”

More supporters of the Kremlin critic gathered around his grave to pay their respects on Sunday. Video shows dozens of people gathered around the grave at the Borisovsky Cemetery in Moscow, with some laying flowers while others stand in silence or take pictures.

Russians overseas also responded to the calls by Navalny’s supporters to protest at polling stations, forming long lines outside the?Russian embassies in Berlin and London.

Navalny’s widow Yulia Navalnaya, meanwhile, was pictured out in Berlin on Sunday, greeting supporters who were rallying against Putin.

Earlier this month, Yulia called for “an all-Russian protest action,” adding, “Alexey called for participation in this noon action against Putin and that’s why it’s so important to me.”

She called on supporters to register their protest by showing up simultaneously at polling booths, and then making their own choice to vote against Putin, write in Navalny, invalidate their ballot or simply leave in silent protest.

Speaking on YouTube, Navalnaya said that the protests “will take place not just in every city, but in every district of every city, millions of Russians can take part and tens of millions more will see it.”

Navalny, Putin’s most formidable opponent,?died aged 47 in an Arctic prison?on February 16, sparking condemnation from world leaders and accusations from his aides that he had been murdered. The Kremlin has denied any involvement in his death.

Voting in the presidential election has seen some acts of civil disobedience, with Russia filing at least 15 criminal cases after people poured dye in ballot boxes, started fires or lobbed Molotov cocktails.

More than 60?Russians have been detained across 16 Russian cities Sunday, according to independent human rights group OVD-Info.

Dissent has effectively been outlawed in Russia since it launched its invasion of Ukraine more than two years ago.

Sunday marks the third and final day of voting, with Russian President Vladimir Putin almost certain to win a fifth term in office.

Voting has been taking place across the country’s 11 time zones – from the far eastern regions near Alaska to the western exclave of Kaliningrad?on the Baltic Coast?– and its?88 federal subjects, including?parts of occupied Ukraine illegally annexed by Russia.

Polling stations in all but the most western regions of?Russia?have closed with the first election results expected after 9 p.m. Moscow time (2 p.m. ET) Sunday.

The turnout in the election surpassed 70% of eligible voters, according to the Election Commission, with the percentage of people voting in the final hours exceeding the final turnout in 2018, according to official figures.

Putin’s reelection would extend his rule until at least 2030. Following?constitutional changes?in 2020, he?would?then be able to run again and potentially stay in power until 2036, which would see him?secure his place as?Russia’s?longest-serving ruler?since Soviet dictator Joseph Stalin.

This is a developing story and will be updated.

CNN’s Seb Shukla and Fred Pleitgen in Berlin contributed reporting.