Two members of security staff at Athletic Club's San Mames stadium were attacked by Olympique Marseille ultras before Thursday night's Europa League tie between Athletic Bilbao and Marseille.
According to Spanish outlet AS, one of the security staff received a knife wound to the neck, whilst the other was stabbed in the hand. The former was reportedly taken to a nearby hospital with wounds in his neck but remains in a stable condition.
Three Marseille supporters have reportedly been arrested in relation to the incidents.
Visiting fans were filmed clashing with the stadium security and throwing flares towards the Athletic supporters inside the San Mames stadium.
The violence that occurred overshadowed the French side's 2-1 win over Athletic, which saw ex-West Ham player Dimitri Payet put the away side in front after converting from the penalty spot.
Ocampos then doubled Marseille's tally in the early stages of the second half to put the French side 5-1 up on aggregate. Inaki Williams got a goal back but the Spanish outfit would've needed to score four goals to progress to the next round.
Unfortunately, the focus wasn't on the outcome of the match but instead, was centred on the horrific events that took place before and during the round of 16 tie.
This isn't the first time the Athletic supporters have come across this sort of behaviour, as
in February a Basque police officer died after clashes between supporters at a Europa League game between their side and Spartak Moscow.
The Marseille fans will be waiting to see who they draw for the quarter finals on the Europa League as we enter into the latter stages of the competition. There are some big names in the draw as the likes of Atletico Madrid, Arsenal and Lazio all won their games on Thursday to claim a place in the draw.