Crowd trouble is a blow for supporters of safe standing, says Arsene Wenger

"I'm surprised even more than disappointed."

Arsenal manager Arsene Wenger fears the recent trouble at West Ham could influence the discussion over whether safe standing should be reintroduced at Premier League grounds.

Opposing fans clashed during the Hammers' EFL Cup victory over Chelsea in midweek at the club's new London Stadium, which has seen other minor incidents of violence since West Ham moved in at the start of the campaign.