Sam Allardyce wants West Ham fans who step out of line at Tottenham to feel the full wrath of the law.
West Ham travel to White Hart Lane on Sunday for the first time since a small group of the club's fans shamed themselves by chanting anti-Semitic abuse in November last year.
Just four days after a Spurs fan was stabbed in an apparent anti-Semitic attack in Rome, a group of West Ham fans chanted "Viva Lazio" and "Can we stab you every week?" while some hissed, mimicking the gassing of Jews in the Holocaust.
West Ham warned their fans that any such behaviour at Spurs - who have a strong link with the Jewish community - would result in a banning order and potential criminal charges.
Allardyce echoed that warning on Friday morning, telling a press conference: "The club has made a statement so you will suffer the consequences if you do anything like that.
"If they do it, I think that's very important that they are identified and they suffer the consequences.
"We live in this society today so if you're made aware of what's acceptable and what's not you've got to be very, very careful about what you choose to chant. If you're made aware of it and it happens you don't have any excuse.
"My message to the fans would be: support the lads on the field and forget about everything else."
West Ham insist they do not tolerate racist or offensive language from their own fans.
And their statement on Friday spelled out the consequences for any fan who does not behave on Sunday.
"Any fan found to be acting inappropriately - including racist, anti-Semitic and homophobic behaviour - will be punished to the full extent of the law and banned from attending matches," the statement read.
"Any such behaviour is completely unacceptable and will not be tolerated by West Ham United.
"West Ham United is rightly proud of its world-famous support home and away and will not allow the reputation of the tens of thousands of Hammers fans who follow the club over land and sea to be tarnished by any unacceptable conduct from a small minority."
Both sets of fans will be monitored closely by the Metropolitan Police, which has warned that officers could arrest any fan chanting the word "Yid".
The warning from Scotland Yard has caused consternation among most Tottenham fans.
Yid is a term for Jew which is often considered derogatory, but some Spurs fans chant the word, or refer to themselves as "Yiddos" or the "Yid Army", as an act of defiance towards those who taunt them over their Jewish fan base.