The documents are also needed that show that the pet has received all the vaccination necessary for international travel (the list of vaccines is available through most local veterinaries). The vaccination should be made not later than 2 weeks before travel (i.e. 5 days before travel is not OK, and this is strictly enforced). The customs will charge the traveler a customs processing fee for every pet. The fee is quite nominal and currently is about 7 US dollars.
Technically translations (to Russian/Belarusian) are required for the documents but this is normally not enforced. If a person arrives with a pet and documents are in English and not translated most of times there will be no problems. Certainly a translation of the pet's documents will make travel more calm and easy.

Upon arrival to Belarus pets need to be registered with a local veterinary service within one month of arrival.

It is generally possible to travel with a pet in local buses, trains and airplanes but better check with appropriate carrier about their policy.
It is also possible to stay with a pet in some hotels and this also needs to be confirmed by hotels directly in each particular case.