The constitutional reform bill allows Russia's President Vladimir Putin to run for president again and bans same-sex marriage, among other changes. Opposition figures said the vote was marred by irregularities.
Russia's referendum on constitutional changes showed voters overwhelmingly approved the amendments that would allow President Vladimir Putin to potentially extend his rule until 2036.
Russia's Central Election Commission said 78% of votes across the world's largest country had supported changing the constitution. Just over 21% had voted against. Turnout was 65%.
The Kremlin called the result a "triumph" and said it demonstrated the public's trust in Putin.
The vote was initially planned for April 22, but it was delayed by the coronavirus outbreak. Putin gave the go-ahead for the referendum last month, claiming the epidemic had peaked.
For the first time, Russians had seven days to cast their ballots. The week-long time frame was introduced to boost turnout, given the dangers of holding an election during the pandemic.
More terms for Putin, ban on gay marriage
The referendum asked Russians if they agreed or disagreed with changes to the country's constitution that included a critical mechanism that would allow Putin, whose term ends in 2024, to run for president again.
The constitutional amendments also include a guaranteed minimum pension, a ban on same-sex marriages, the inclusion of ''a belief in God'' as a core value, and it would emphasize the primacy of Russian law over international norms.
Although Russia's parliament had already approved the reforms, Putin put the plan on the ballot, hoping to get public support for the changes, which he said were needed to ensure stability and cement what he described as Russian values.
"We are voting for the country ... we want to pass on to our children and grandchildren," Putin said on Tuesday.
Navalny: Results are 'a huge lie'
Russia's divided opposition struggled to mount a campaign against the referendum, weakened by years of political repression and with little access to state-controlled media.
"The opposition here in Russia is very divided, including on this vote, some people have said that you should stay home, that you should boycott the vote, some people have said that you should come out and be counted, to say you are against this vote," DW's Moscow correspondent Emily Sherwin explained.
Opposition politician Alexei Navalny said Putin is seeking to make himself "president for life." He and other critics of the Kremlin say the election was not fair and believe the constitutional reform will almost certainly lead to Putin extending his grip on power.
As the results rolled in on Wednesday evening, Navalny dismissed the figures, saying they don't reflect reality.
"The 'results' they have just announced are a fake and a huge lie. They don't have anything to do with the opinion of Russian citizens," Navalny said.
"We'll never recognize this result," Navalny told supporters in a video.
Golos, an independent election monitor, has said it received hundreds of complaints of electoral violations, including people voting more than once and claims employers are putting pressure on staff to cast ballots.
''We look at neighboring regions, and anomalies are obvious. There are regions where the turnout is artificially (boosted), there are regions where it is more or less real,'' Grigory Melkonyants, co-chair of Golos, told the Associated Press.
Russian authorities are said to have mounted an operation to persuade teachers, doctors, public sector workers and others who are paid by the state to vote in favor of the constitutional amendments.
The Kremlin also sought to boost turnout and support in the referendum by offering prizes, ranging from gift certificates for cars and apartments. Voters from eastern Ukraine who have Russian passports were reportedly bussed across the border to vote.
jcg/ng (Reuters, AP, AFP)