Opposition leader Sergei Udaltsov speaks through a loudspeaker to crowds at tha May 6 March of a Million event.
Moscow City Hall has turned down opposition activists' application to march down Tverskaya Ulitsa to the Kremlin during its planned June 12 protest, suggesting instead that demonstrators move to a site outside the center.
City Hall approved the request for 50,000 participants, but proposed that demonstrators head down Frunzenskaya Naberezhnaya along the Moscow River, with a rally at Andreyevsky Bridge.
The march route requested by the opposition is the same used by a May Day march headed by President Vladimir Putin and Prime Minister Dmitry Medvedev before they switched jobs.
Opposition march organizers said the city's suggested route was unacceptable.
"The refusal is motivation to hold our event on Red Square," Left Front leader Sergei Udaltsov wrote Twitter. "We will insist on holding it in the very center."
Udaltsov announced earlier this week that organizers had submitted an application to hold a second March of a Million event, which was to with a rally at Borovitskaya Ploshchad.
But city authorities said there was simply no space in the center for the demonstrators.
"Different locations have been given to other events," head of City Hall's regional security Alexei Mayorov told RIA-Novosti.
Mayorov said organizers could take the offer or cancel plans for the march.
Authorities also refused a request by Union of Communist Youth head Denis Zommer for a march down Tverskaya Ulitsa on the same day.
Udaltsov said a meeting to discuss plans would be held Saturday, June 2, near the statue of Abai Qunanbayuli at Chistiye Prudy, the site of a week-long, round-the-clock opposition rally earlier this month.