Sunday marks the final day of the three days of voting in Russia's presidential election. Authorities appear to be prepared to quash any show of dissent.

Four candidates including President Vladimir Putin are running for the seat, but Putin is almost certain to secure his fifth term.

Critics of Russia's invasion of Ukraine, including a former lower house legislator, were not allowed to run.

The widow of opposition leader Alexei Navalny who died in February has called on people to use the election to protest Putin and his government.

Yulia Navalnaya urged Russians to come to polling stations at noon on Sunday to vote for any candidate but Putin or to write "Navalny" on the ballot paper.

Russian authorities have repeatedly warned that people who obstruct voting will be punished and could face imprisonment.

Observers say that Putin and his government appear intent on suppressing any protests to accomplish a sweeping victory.