Vladimir Putin casts ballot in Russia's election

Russian President Vladimir Putin has cast his ballot in the presidential election, seeking a mandate for a fourth term.

Putin is certain to win in Sunday's election, so voter apathy is widespread. Authorities have spent unprecedented funds to get out the vote to ensure he has a strong mandate for his next six years in office.

Some 145,000 observers are monitoring the voting in the world's largest country, including 1,500 foreigners and representatives from opposition leader Alexei Navalny's political movement.

Navalny himself is barred from running. Putin faces seven challengers but none poses a serious threat.