Updated at 1:13 p.m. ET
(AP) MOSCOW - The Obama administration on Monday congratulated the Russian people for turning out to vote in big numbers in this weekend's presidential election but said it was concerned by allegations of massive fraud and pointedly did not mention victor Vladimir Putin by name.
In a statement, the State Department said the U.S. would work with Russia's "president-elect" once the vote is certified. It noted that European observers had determined that "the election had a clear winner with an absolute majority." At the same time, it pointed out that the monitors had raised issues with the fairness of the campaign, partisan use of government resources and procedural irregularities on election day. It said those charges must be fully and credibly investigated.
"The United States congratulates the Russian people on the completion of the presidential elections, and looks forward to working with the president-elect after the results are certified and he is sworn in," State Department spokeswoman Victoria Nuland said in the statement. She also welcomed some improvements in the electoral process but said additional steps would be needed to make it more transparent.
Putin won more than 63 percent of the vote according to the nearly complete official returns from Sunday's election. But the opposition and independent observers say the election has been marred by massive fraud and thousands of Russians gathered Monday for a massive rally to challenge Putin's victory, chanting "Shame!" and "Russia without Putin!"
The demonstrators are contesting the outcome of the vote, pointing to a campaign heavily slanted in Putin's favor and to reports of widespread violations in Sunday's ballot. International election monitors pointed at the lack of real competition and said the vote count "was assessed negatively" in almost a third of polling stations observers visited.
"We urge the Russian Government to conduct an independent, credible investigation of all reported electoral violations," Nuland said.
Putin's win was assured as he faced a weak slate of Kremlin-approved candidates and many across the vast country still see him as a guarantor of stability and the defender of a strong Russia against a hostile world, an image he has carefully cultivated during 12 years in power. He has denounced his foes as Western stooges working to weaken Russia.
Here's a list of the main violations reported during Sunday's ballot:
Voting outside designated polling stations
According to the independent Russian elections monitor Golos, many voters cast their ballots either right at their state-run enterprises or under their bosses' watchful eyes, while others were bused to polling stations where they were not on voter rolls and where there was little oversight over voting.
Use of absentee ballots
Over 2 million absentee ballots were used in the election, and Golos monitors said that allowed for widespread violations. Many workers of state-controlled enterprises were forced to obtain absentee ballots and then vote under supervision. Absentee ballots were also used in multiple voting.
Voting more than once
Golos said "carousel voting," in which busloads of voters are driven around to cast ballots multiple times, also was widespread. Often, the offenders walked into polling stations wearing ribbons around their arms or with special marks in their passports, which they presented as identification. Election officials then identified those people as carousel voters and gave them the ballots of voters who were unlikely to show up.
A web-camera video from a village in the southern province of Dagestan shows several men standing at an electronic ballot box and feeding dozens of ballots into it for several minutes. Central Election Commission chief Vladimir Churov described the incident as the local election officials' "fatal mistake." Churov explained that those ballots had been filled out by sick or elderly people voting at home and that election officials were merely depositing them in the ballot box. In the end, voting results at that polling station were annulled after the complaints.
Paid to vote
Another video shows an activist who signed up on an Internet forum to take part in multiple (carousel) voting for 1,000 rubles ($33). The video, shot by the activist, shows him meeting the organizers at a subway station and then being bused to a nearby polling station. The activist and a dozen other people are shown lining up to receive the ballots and then voting at the station. Their names appear on a separate list at the polling station.
Not free or fair
Andrei Buzin, an election expert at Golos, said that the falsifications were not widespread enough to have left Putin with less than 50 percent of the vote and require a runoff, but the vote was still skewed. "I wouldn't call these elections free or fair," Buzin said.
The Organization of Security and Cooperation in Europe said "there was no real competition, and abuse of government resources ensured that the ultimate winner of the election was never in doubt." The watchdog noted that the election "process deteriorated during the vote count, which was assessed negatively in almost one-third of polling stations observed."