I think, although I am by default very sceptical about these things, this does genuinely seem to be more than that for once. And, significantly, it's not just in the centre of Minsk like previous minor opposition demos, but appears spread throughout the country.Though despite some heroic camerawork looks a bit more like snowflake outrage than a mass popular uprising.
There are a few Telegram channels aggregating the reports but this one (very opposition) has a pretty good collection - Telegram Web
The early scenes of riot police running away or being beaten back have disappeared now they have numbers, water cannon and are firing baton rounds. But protests still seem to be going on in force. Looks like it's going to be a long night in any case.