Tottenham intend to take strong action and will impose stadium bans against any supporters found guilty of racist behaviour during Sunday's 2-0 defeat to Chelsea.
A first-half brace from Willian gave Frank Lampard's visitors a deserved victory in north London but an incident after the hour marred the contest.
After objects were thrown at Chelsea players, Blues defender Antonio Rudiger told the match officials he had been subjected to racist chanting.
Then, on three separate occasions, an announcement over the Tottenham Hotspur Stadium public address system called for racist behaviour that was "interfering with the game" to cease.
"We are now conducting a thorough investigation which will include liaising with Chelsea and their players for their observations," a club statement from Tottenham read.
"Any form of racism is completely unacceptable and will not be tolerated in our stadium.
"We take any such allegations extremely seriously and shall take the strongest possible action against any individual found to be behaving in such a way, including stadium bans."
Spurs head coach Jose Mourinho similarly offered a guarantee that his club will take action.
"I saw nothing. I saw the referee following the protocol, I saw the referee speaking with [Andre] Marriner [the fourth official], I saw the referee coming to me and to Lampard and telling us what was going on," Mourinho told Sky Sports .
"Our club will deal with it. Every club is together on this situation and of course we are disappointed."
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