Russia's largest independent vote monitoring body has echoed international criticism of the weekend's parliamentary elections.
Golos said the vote was not free, not competitive and took place under pressure.
President Vladimir Putin's United Russia party won an overall majority, securing 64.1% of the vote.
The Communist Party came a distant second with 11.6%, while two other pro-Kremlin parties - the ultra-nationalist LDPR and the centre-left A Just Russia - got 8.2% and 7.8% respectively.
Lilia Shibanova of Golos warned that Russians could not have confidence in the results.
Golos fielded 2,500 observers on election day, using journalists with access to polling stations. Domestic observers not affiliated to political parties are banned under Russian law.
Meanwhile, Russian President Vladimir Putin defended his party's landslide victory, calling it a big personal endorsement.
A Kremlin spokesman said the election had been free and fair and that any allegations of voting irregularities would be investigated.
Mr Putin said the margin of victory was a sign of political stability and thanked the electorate for turning out in high numbers.
