Russian President Vladimir Putin was slated to win the country's presidential election, state-run exit polls showed Sunday.

The government-run VTsIOM pollster showed the 71-year-old had won a landslide, having secured an estimated 88% of the vote in the three-day election that included no real opposition candidates.

The exit polls were released following the closure of polling stations in Russia's westernmost region of Kaliningrad on Sunday evening.

If confirmed, the result would be a record for Putin, who received 76.7% of the vote in the last presidential election in 2018.

The former KGB spy would become Russia's longest-serving leader in more than 200 years, overtaking Josef Stalin.

Putin is now poised to extend his nearly quarter century of rule for six more years having presided over a thorough crackdown on dissent.

International observers did not monitor the election across the vast country which reaches across 11 time zones.

Election marred by alleged Ukrainian attacks

The election took place just over two years since Putin triggered the deadliest European conflict since the Second World War by ordering the full-scale invasion of Ukraine, which he labels a "special military operation."

During the poll, several Russian regions were allegedly attacked by Ukrainian missiles and drones, which killed several people.

After the exit poll was announced, Ukrainian President Volodymyr Zelenskyy described Putin as a power-hungry "dictator."

"It is clear to everyone in the world that this figure — as has happened so often in history — is simply sick from power and is doing everything he can to rule forever. There is no evil he will not commit to prolong his personal power," Zelenskyy said on social media.

US decries poll as 'not free nor fair'

The White House denounced the Russian election as "obviously not free nor fair given how Mr. Putin has imprisoned political opponents and prevented others from running against him."

Germany's Foreign Ministry said the election result would "surprise nobody."

"Putin's rule is authoritarian, he relies on censorship, repression & violence. The "election" in the occupied territories of Ukraine are null and void & another breach of international law," the ministry wrote on X, formerly Twitter.

The Tagesspiegel newspaper cited a spokesperson for German President Frank-Walter Steinmeier as saying he would not send a letter of congratulations to Putin.

UK Foreign Secretary David Cameron dismissed the exit polls, saying on X, formerly Twitter: "This is not what free and fair elections look like."

Russian state TV hails Putin's 'colossal' public support

Former Russian leader Dmitry Medvedev congratulated Putin on his "splendid victory," while Russian state-run television praised "colossal support to the president" and the "unbelievable consolidation" of the country behind its leader. 

Supporters of Putin's most prominent opponent Alexei Navalny, who died in an Arctic prison last month, had called on the public to come out at a "Noon against Putin" protest to show their anger at Putin's crackdown.

News agencies reported an increase in younger voters at noon at polling stations in Moscow, St Petersburg and Yekaterinburg, with queues of several hundred people and even thousands.

Arrests amid protests

At least 80 people were arrested for protesting on Sunday across Russia, according to OVD-Info, a group that monitors crackdowns on dissent.

Navalny's widow, Yulia, appeared at the Russian embassy in Berlin to cheers and chants of "Yulia, Yulia." 

She said she had written her late husband's name on her ballot.

Meanwhile, President Putin said he had agreed to a prisoner swap involving Navalny prior to his death, adding it is "sad" when someone dies.

Putin said the main condition for the exchange was that the opposition figure would not return to Russia.

Navalny was Putin's fiercest domestic opponent. His allies and Yulia accuse Putin of having him murdered, something the Kremlin denies.

A concert on Moscow's Red Square is being staged on Monday to mark 10 years since Russia's annexation of Ukraine's Crimea peninsula — an event that is also expected to serve as a victory celebration for Putin.

Putin warns of potential Russia-NATO conflict

Putin also said a conflict with NATO cannot be ruled out at a press conference in Moscow to mark his victory.

"Everything is possible in the modern world," the Russian president said when questioned about the possibility of such an event, warning such a conflict "will be one step away from a full-scale World War Three."

"I think hardly anyone is interested in this," he said.

Last month, French President Emmanuel Macron said he could not rule out deploying ground troops in Ukraine in the future.

While many Western nations distanced themselves from Macron's views, some in Eastern Europe expressed support.

Putin in his press conference said Moscow knows that NATO soldiers are already deployed in Ukraine. The Russian leader did not provide any proofs for his assertions.

He also thankedRussian troops fighting in Ukraine saying, "No matter who or how much they want to intimidate us… It has not worked now and will not work in the future. Never."

jsi, mm, ss/wd (Reuters, AFP, dpa)