Kremlin-backed candidate Sergei Sobyanin has won the election for mayor of Moscow, results released by Russian election officials indicate, reports BBC.
After a nearly complete vote count, Mr Sobyanin secured 51.3% - just above the 50% threshold needed to avoid a second-round ballot.
His main rival, opposition leader Alexei Navalny, obtained 27.3%.
He called for a run-off and refused to recognize the results, saying they had been "deliberately falsified".
Mr Navalny said he had won enough votes to force a second round and that the count had been marred by "many serious violations".
Mr Sobyanin said the election had been transparent and that a run-off ballot was unlikely.
"Judging by the percentage of the counted ballots, we can say with a high certainty that there will be no second round," he told supporters earlier on Monday morning.
If there is any serious suggestion of the election being rigged, large-scale protests will probably return to Moscow's streets, the BBC's Daniel Sandford reports from Moscow.
In late 2011, Moscow was the scene of the biggest anti-government protests since Soviet times after a general election marred by allegations of ballot-rigging.
Mr Navalny had earlier warned that if he was denied a run-off, he would "appeal to the citizens and ask them to take to the streets of Moscow".
"Right now Sobyanin and his main supporter Vladimir Putin are deciding whether to have a relatively honest election and to have a second round, or not," he said on Sunday, as partial results were still coming in.
The pro-democracy leader is currently on bail after being found guilty of embezzlement in what he insists was a political trial.