A Thessaloniki prosecutor on Tuesday ordered a preliminary investigation to determine if the necessary safety standards had been observed by the organisers of a Manu Chao concert held in the city’s port on Monday evening.

The investigation will be held in response to a bloody scuffle that broke out between members of the audience during the event, in which a 40-year-old man was slightly injured by a sharp object.

The 57-year-old organizer of the music event, who was arrested on charges of exposing the audience to danger, has been released due to lack of incriminating evidence against him since all the required safety measures had been observed, including fire safety and the presence of private security.

The incident occurred a few minutes after the popular singer appeared on stage on Monday evening when, according to eyewitnesses, two groups of people, apparently fans of rival football clubs, clashed with each other. A man was slightly injured and was taken to hospital.