The Moscow Times reported that Medvedev's popularity is above 70 percent and the Russian presidential front-runner could win by a large margin than his ally, President Vladimir Putin, did in 2004 -- when Putin collected 71.3 percent of the vote.

"Anything above 85 percent for Medvedev would be very improbable because there are core Communist voters and Zhirinovsky's voters," said a Medvedev campaign official, speaking to the newspaper on condition of anonymity.

Communist leader Gennady Zyuganov, Liberal Democratic Party leader Vladimir Zhirinovsky and Andrei Bogdanov, an independent, are also running for president.

Alexei Mukhin, an analyst with the Center for Political Information, said Putin -- who hand-picked Medvedev as his successor -- would want a vote so high that the election is open to question.

"This would make Medvedev a less legitimate president in the eyes of the West. Medvedev would then need a stronger Putin in order to legitimize his government," Mukhin said.