Chelsea have warned their fans they will ban anyone who is caught causing trouble at their game at West Ham.
This is the first time the rivals have faced each other at the London Stadium, and there are concerns over crowd violence.
The visit of Chelsea, who have sold out their allocation of 5,182 tickets, has put both clubs on alert.
In a statement last night Chelsea said: "Even if arrests are not made on the night, the police will work with the clubs to identify and arrest individuals. Chelsea will ban any of our supporters shown to be involved."
On Monday, West Ham issued a statement in which they said any troublemakers would be "identified and dealt with accordingly".