Amsterdam football club Ajax said on Thursday it is carrying out its own investigation into Wednesday afternoon’s clashes between supporters and Italians ahead of the club’s crucial Champions League tie.

Fighting broke out between Ajax fans and supporters of the Italian Forconi movement, who were protesting about high fuel prices and tax increases, according to media reports.

But it is unclear why the trouble started, news agency ANP reported.

Later there were clashes between Ajax and AC Milan fans by the San Siro Stadium. Several Ajax supporters were stabbed during those disturbances and three remain in hospital.

‘We want to know exactly what happened and have been in touch with our Italian colleagues,’ a club spokesman said, but declined to comment further.

The match ended in a 0-0 draw.