Newcastle United fans have been warned not to taunt new Sunderland boss Paolo Di Canio with fascist salutes during Sunday's North East derby match. The Italian was fined for making right-arm salutes to Lazio fans as a player in 2005.
Northumbria Police said such gestures would not be treated "as a joke".
Ch Supt Steve Neill said: "Offensive gestures, particularly those with a suggestion of racist connotations, are completely unacceptable.
"We will take positive action against anyone seen acting in an offensive or racist manner."