Napoli has been fined
The European governing body has also threatened the Serie A club with playing a European match behind closed doors if the issues at its Stadio San Paolo resurface within the next five years.
A UEFA statement read: "Italian club SSC Napoli have been punished by the UEFA Control and Disciplinary Body for the inappropriate conduct of their supporters, insufficient organisation in the stadium and non-respect of UEFA directives related to stadium security at their UEFA Europa League Group F match against Swedish opponents AIK on 20 September."
Napoli will also be banned from selling tickets for parts of the main stand for its next European game at home to Dnipro on
UEFA said if satisfactory repairs have not been carried out by
Napoli has three days to appeal the decision.
Inter Milan president Massimo Moratti admits he has a difficult decision to reach as he considers whether Andrea Stramaccioni should remain as the club's head coach.