Belarus (Bbabo.net):

Russia has changed the rules for the entry of foreigners through air checkpoints. So, now the citizens of Belarus, Armenia and Kyrgyzstan, who have chosen air transport to travel to Russia, will need to present a negative test result for COVID-19 by PCR at checkpoints in the mobile application "Traveling without COVID-19". In this case, it is not necessary to use the application by arriving by train - a document confirming the passage of PCR testing no earlier than 72 hours before the trip will do.

bbabo.Net