Police may appear to form a larger group than fans attending at Sofia Stadium on Wednesday night.
A total of 1,500 policemen are watching for the security before, during and after the match between the European Club Champion and Bulgaria's Cup winner.
Liverpool fans, who are not expected to exceed 200, will be guarded off by police on their way from hotels to the stadium. Police will also watch out for the public order in clubs where Liverpool fans gather across the capital city.
Meanwhile, booksellers recorded low interest from ticket buyers, which can be explained with the scarce chances of CSKA to beat their Red colleagues from Merseyside.