Manchester City fans have concerns travelling to Naples for their looming Champions League date against Napoli.

The Sun reports City fans are on red alert after SIX Bayern Munich supporters were stabbed ahead of Tuesday's 1-1 draw at Napoli.

The German victims all suffered the traditional calling card of Napoli's notorious 'Ultras' and were slashed across the buttocks by knife-wielding thugs on scooters.

Although none of the fans were seriously hurt, it will raise fears for the safety of City fans whose side are due in the Italian port city for a key Champions League clash on November 22.