Clashes between rival supporters marred West Ham's EFL Cup fourth round win over Chelsea at the former Olympic Stadium on Wednesday night.

Skirmishes broke out towards the end of the Hammers' impressive 2-1 fourth-round win as police and stewards battled to maintain segregation behind the goal being defended by West Ham.

Slaven Bilic was eager to focus on his side's display after the match, but admitted he was disappointed by the ugly scenes.

He said: "I can say only that I have noticed it of course and it was there but I was concentrated on the game.

"I was more focused on telling Cresswell not to watch it and to watch the game.

"I don't know what happened, but whatever happened we are totally against it as a club and as a team.

"For those kind of things to happen, particularly in England, it cannot happen."

This derby was billed as the biggest footballing test for the London Stadium so far, on a night when basketball and track cycling competitions were also taking place on the former Olympic Park.

The capacity is capped at 57,000 and 45,957 were in attendance, along with a heavy police presence.

Chelsea sold out their allocation of 5,182 tickets and, with the Hammers 2-0 up, trouble broke out.

Fans could be seen attempting to make it past stewards to reach rival supporters while seats were also ripped out and thrown.