A section of West Ham fans appeared to mock the stabbing of a Spurs fan in Rome on Sunday during the Hammers' 3-1 defeat at White Hart Lane.
A group of away fans also appeared to mock Jews being gassed during the Holocaust, while chanting the name of Adolf Hitler.
Such actions have enraged Tottenham fans - who have a historic connection with the Jewish community - and the north London club have promised to help find the culprits.
Sam Allardyce: "Yes. It's a small minority but at the end of the day a small minority can make themselves heard at football matches if they really want to and we must deal with it.
"The good thing is with security cameras and CCTV cameras, it's difficult for them to get away with it. Hopefully we can pick out those people and punish them in the right way.
"It's very, very disappointing to hear what has been said and done by a small minority of fans. No one condones that sort of behaviour.
"I don't wish to hear any of that sort of chanting in the game of football anywhere in this country.
"We have to continue to do all we possibly can for it not to happen.
"If we punish the people who have done it in the right way I think we will cut it out and stop it.
"I refused to be drawn on the matter in the immediate aftermath of the defeat.
"I was doing a press conference after the game and had no idea what had happened and what had been said or done.
"I wasn't prepared and didn't want to comment having not heard what went on.
"I don't know how I was supposed to react to something I didn't know anything about.
"You are in a very difficult position. We had just been beaten 3-1 by Tottenham. I wasn't in the best mood. I am not expecting the question.
"I am expecting to talk about football and I am a football manager. I didn't want to comment on it. Now, like everyone else - I don't condone it."