This is probably related to this colour revolution thread from yesterday.
UAZ "Patriot" MIA trailers with barbwire now deployed in Minsk, capital of Belarus.
Additional forces deploying, including water cannons and a machine setting up barbwire.
Random photo of Belarus forces in Minsk, can't confirm for certain that it was taken today though.
Like twenty years ago there was a proposal to merge Belarus and Russia into an EU-like entity with open borders.