Preliminary reports from Sunday's presidential election in Russia give incumbent President Vladimir Putin the overwhelming lead, while support for all but one of the five opposition challengers remains in the single digits.

The chief of Russia's Central Election Commission, Alexander Veshnaykov, says President Putin is leading in the polls, with 66 percent of the vote, while his five rivals trail far behind, as was widely expected.

Mr. Veshnaykov said the first figures are based on early vote counts in the Russian Far East, Siberia and part of the Urals. He briefed reporters at commission headquarters one hour after the 95,000 polling stations across Russia closed.

Earlier, electoral officials said that more than 50 percent of voters nationwide had cast ballots, making the election valid.

Overall, voting lasted nearly 22 hours, stretching across 11 time zones, before ending late Sunday. No serious incidents or violations were immediately reported.

Vote counting will continue overnight and into Monday morning, at which time first results are expected.