A blast and subsequent small-scale fire was reported on Sunday evening outside the northern Athens building housing the Greek Super League, the country’s first division pro football tournament.

Remnants of firebombs were found at the scene, while the blaze was quickly extinguished by the fire brigade.

Authorities believe the attack is directly related to the Olympiacos Piraeus-Panathianikos Athens derby of the previous day, which ended with a controversial 2-1 victory by league-leading Olympiacos in the wake of a handful of questionable referee calls.