Levski and Slavia Sofia fans clashed at the Georgi Asparuhov Stadium at the end of their Bulgarian First League match on Saturday.
Levski lost 2-1 to Slavia and have now gone seven consecutive games without a win in the league.
After the final whistle, angry Levski fans burst out of their stand and approached a nearby terrace containing a group of Slavia fans who were goading them.
Both sets of fans began throwing various objects at each other. Some Levski fans were also seen entering the terrace and punching and kicking their opponents before stewards and police stepped in.
Several Levski fans were arrested as a result.