Russian authorities have banned the March for Siberian Federalisation scheduled for August 17 and threatened to block the BBC Russian service over its coverage of separatist protests.
The media watchdog may block the website of the BBC Russian service over an interview with Artyom Loskutov, an organiser of the March for Siberian Federalisation, the newspaper Izvestiya reported on Tuesday.
The federal communications monitoring service has sent a letter demanding the interview be deleted for violating a recently passed law against "calls to mass unrest, extremist activities or participation in illegal public events".
It is believed the authorities in Novosibirsk - Siberia's largest city - see the march as flouting Russian laws and it is being banned 'to ensure the stability of the constitutional order, territorial integrity and sovereignty of the Russian Federation'.
Organisers may seek to appeal the ban or reapply for a new march.
Most of Russia's oil and gas output comes from western Siberia, but the region lags behind Moscow, St Petersburg and some southern areas in quality of life ratings.