President Vladimir Putin won a record landslide in Russia's election on Sunday, cementing his already tight grip on power in a victory he said showed Moscow had been right to stand up to the West and send its troops into Ukraine.

Putin, a former KGB agent who first became leader at the end of 1999, made it clear that the result should send a message to the West that its leaders would have to reckon with an emboldened Russia, whether in war or in peace, for many more years to come.

The outcome means Putin, 71, was set to embark on a new six-year term that would see him overtake Josef Stalin and become Russia's longest-serving leader in more than 200 years if he completes it.

Putin won 87.8% of the vote, the highest ever result in Russia's post-Soviet history, according to an exit poll by pollster the Public Opinion Foundation.

The Russian Public Opinion Research Centre put Putin on 87%. First official results indicated the polls were accurate.

The United States, Germany, the United Kingdom and other nations have said the vote was neither free nor fair due to the imprisonment of political opponents and censorship. (Reuters)