According to reports, Arsenal supporters were attacked and hurt before the Champions League match against Lens.
The Gunners travelled to France to play Lens in their second Champions League group-stage clash.
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Before the game, it was reported that some Arsenal supporters were attacked in the streets of France and were left injured by the attack.
One supporter was reportedly left "laying in the street" in Lens shortly before the game began as a result of the incident.
The attack on Arsenal fans
According to reports from the Sun, It is thought that French and British authorities are collaborating to investigate the attack.
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According to Sky News, at least one fan apparently required medical assistance on the spot but the number of Arsenal supporters who were transported to the hospital is unknown.
Police in France had earlier categorised the Champions League match as "high-risk" because of the anticipated attendance of over 1,800 Arsenal supporters in Lens on Tuesday night.
Meanwhile, Arsenal lost shockingly to Lens, who prevailed 2-1. Gabriel Jesus handed the Gunners the lead after only 14 minutes.
A few minutes later, Adrien Thomasson's powerful goal against David Raya gave Lens the equaliser.
Elye Wahi won the game for Lens on the night as the Gunners' unbeaten record ended with a loss in France.