"The organisers of the rally planned on Academician Sakharov Avenue notified the Russian Interior Ministry in Moscow that [opposition figure] Lubov Sobol and other participants of the rally were going to organise provocations during the event", the Moscow police said in a statement.
The Moscow city government authorised the demonstrations at Academician Sakharov Avenue to be held from 2 p.m. (11:00 GMT) to 4 p.m. (13:00 GMT) on 10 August.
"As of 2 p.m., about 7,000 people have joined the event", the Moscow police said in a statement.
The previous rallies were unauthorised by the Moscow authorities.
In late July, a number of pro-opposition candidates held rallies and called for acts of civil disobedience to protest them being barred from participating in the September 8 election after they failed to gather the needed amount of valid signatures of support.