Trouble erupted near the end of the match in east London, which West Ham won 2-1 thanks to goals from Jarrod Bowen and Said Benrahma.

One of the officers has a suspected broken wrist while another needed stitches for a head injury. Two other officers were struck on the head during the disorder.

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Chairs and flares were thrown from within the away section and officers had to intervene using protective equipment to restore calm.

One man was arrested for the alleged assault on the officer who suffered a suspected broken wrist.

Twelve people were arrested for other offences unrelated to the assaults on officers.

West Ham boss David Moyes said after the game: "The players' job is to get on with it, and I thought they did.

"The more we look at it, we don't want any trouble. We're in a different society and a different world now and it's not what any football club wants to have connected to them, and I certainly don't want that at West Ham."

Anderlecht strongly condemned the behaviour of their supporters and will work with UEFA to ensure action is taken.

A club spokesperson said: "The club will take this onwards with supporters because we don't tolerate this kind of behaviour, not in our home stadium and not away. We will take it up with the fans and definitely UEFA and we strongly condemn this. We want to apologise to West Ham for this behaviour."

Moyes added: "It's good for the press officer to stand up for the club. It's a big credit to them as they're a really good football club. They want to protect their own club and rightly so.

"Everyone's focus is taken away when there's crowd trouble in some way. I didn't have any interest in it as it's one of those things you don't want to talk about. I don't want to draw any more attention to it."