Russians appear to have strongly backed constitutional reforms that could keep President Vladimir Putin in power for two more terms.
Hours before polls had closed, preliminary vote counts were reported from the Central Electoral Commission.
Ria Novosti said 70.8% of voters supported the measures, after 10% of polling stations had been counted.
The proposed reforms would reset Mr Putin’s term limits to zero, allowing him to stay in power until 2036.
Opposition members have said he is trying to become “president for life”, a claim Mr Putin denies.
Read more: BBC