A West Ham fan was taken to hospital after a group of supporters were attacked by what witnesses say were a set of Eintracht Frankfurt ultras, German police have confirmed.
In the early hours of Wednesday morning, two vans stopped outside a pub in the Hesse city where a group of Hammers fans were drinking.
Witnesses say around 15-20 people donning face coverings and appearing to be fans of Europa League opponents Eintracht got out of the vans, before entering the pub and attacking the visiting supporters.
Police have confirmed that one fan was injured in the incident.
The attackers then got back into the vehicles and left the scene. Police said they were unable to locate the vans, with one of them having a local number plate.
“The injured guest, a 34-year-old man from Britain, was taken to hospital for medical treatment,” Frankfurt police said in a statement.
West Ham are taking a 2,600-strong contingent of away fans into the stadium for Thursday night’s Europa League semi-final second leg - with more expected to travel and watch the game from the city.
The Hammers were targeted by a set of Frankfurt ultras ahead of their last-16 tie with Sevilla, Eintracht having played the night before at nearby Real Betis.
During the first leg, which the Bundesliga side won 2-1, a pair of visiting commentators were set upon by home fans at London Stadium.
Police in Germany had talked up having an officer on every street corner on Thursday ahead of the game.