Check out this footage of a brawl in the stands at the Cleveland Browns vs. Cincinnati Bengals game on Thursday night ... where the combatants don't seem to care about COVID-19.

Unclear what started the incident at FirstEnergy Stadium in Cleveland ... but you can clearly see security working like hell to try and break things up as quickly as possible.

The silver lining ... everyone seemed to be wearing masks! So, at least there's that!

Only 6,000 fans were allowed into the stadium to watch the game due to social distancing policies in place -- and all 6,000 reportedly had to sign a "health promise" saying they would not enter the facility if they were sick.

The "pledge" also says fans will wear masks, social distance, etc. Wonder if it said anything about fighting?!

The good news ... the Browns players seemed to channel that fighting spirit on the field -- defeating the Bengals in a 35 to 30 victory.