Trouble flared at the Georgi Asparuhov stadium on Thursday as Levski didn't progress to the second qualifying round of the Europa League.
A Bulgarian league match between Lokomotiv Plovdiv and CSKA Sofia was halted for around 20 minutes on Sunday after a massive brawl broke out between rival fans.
Hebar Pazardzhik and Minyor Pernik fans fought on the terraces during their third division match on Saturday, halting play for 10 minutes.
Irate Levski fans clashed with riot police after a defeat of their team.
CSKA Sofia hools caused problems at the third league match against Minyor Pernik.