On Friday 19 June 2020, an agreement was signed between Minister of foreign affairs of Russia and Belarus regarding mutual recognition of each others’ visas. Under this agreement, citizens of third countries can enter, stay and leave Russia and Belarus with a single visa of Russia or Belarus. One visa will be enough to enter in both countries.
This means if a foreigner holds a valid visa of Russia, he/she would be allowed to enter Belarus with Russia visa without any need of Belarus visa. He/she can stay in Belarus and exit within the validity of his/her Russia visa. This is exactly similar to the Schengen visa system where a foreigner is allowed to enter all 26 Schengen countries with a single visa of any Schengen country.
The same will be applied to Belarus visa holders. A person holding a valid visa of Belarus would be allowed to enter Russia without obtaining Russia’s visa.
Foreigners can move between Russia and Belarus by Rail, by air or by road.