West Ham United said they are working to find supporters who allegedly attacked two German radio commentators during Thursday's 2-1 home defeat to Eintracht Frankfurt in the first leg of their Europa League semifinal.

Reporters Philipp Hofmeister and Tim Brockmeier, who work for German regional broadcaster Hessischer Rundfunk, said they were attacked after Michail Antonio scored in the 21st minute to level the game at 1-1 and were then moved to other seats at half time.

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West Ham said they were aware of the incident and would work to identify the offender.

"In line with our zero-tolerance approach, anyone identified will have their details passed to the police," a spokesperson for the Premier League club said.

"They will be given an indefinite ban and be unable to enter London Stadium and travel with the club. There is no place for this kind of behaviour."

Hofmeister wrote on Twitter that they were "doing OK."

"Best wishes to all West Ham supporters who love football and respect their opponents," he added.

West Ham, who are seventh in the Premier League, host Arsenal in the league on Sunday before travelling to Frankfurt for the return leg next week.