In Moscow, the city election commission chairman said foreign observers had not reported any abuses. Voting was proceeding "calmly and according to schedule", said Vladimir Churov, chairman of the Central Electoral Commission.
This followed accusations -- denied by the Kremlin -- that skewed media coverage, intimidation of opposition parties and the liberal use of government resources to promote United Russia had made the contest one-sided even before polls opened.
"These are the dirtiest, most irresponsible elections," Communist Party leader Gennady Zyuganov said. "... They have thought up at least 15 ways to entrap and betray voters".
Former world chess champion and opposition icon Garry Kasparov denounced the election after intentionally spoiling his ballot paper at a snowbound central Moscow polling station.
"They are not just rigging the vote, they are raping the whole electoral system," Kasparov said. "These elections are a reminder of Soviet elections when there was no choice." Kasparov has little popular support inside Russia.
ECONOMIC BOOM BOOSTS PUTIN
The opposition's complaints were irrelevant for many of the 106 million registered voters. Russians have enjoyed an oil boom under Putin that has boosted wages and living standards.
"I remember how we lived before, and it has only been under Putin that the country has picked itself up," said Tatyana, a 61-year-old actress who declined to give her family name.
The West's main election watchdog, the ODIHR, was not monitoring the vote, creating a headache for foreign governments which normally rely on its judgment about election fairness.
The ODIHR pulled out after a row with Moscow over delays in issuing visas. Fewer than 300 foreign observers, half from former Soviet republics, have been accredited for the election.
Putin has said the election will be "honest, as transparent as possible and open". He has told Western governments to keep their "snotty noses" out of Russia's affairs and stop trying to undermine the election.
Election monitors Golos said they had collected reports of violations ranging from police detaining observers to groups offering gifts in exchange for a pro-Putin vote.
In the second city of St Petersburg, a party competing against United Russia said people were being bussed around the city voting in one polling station after another. One Kremlin opponent said he saw one such bus being driven by a policeman.
