Tensions were running high in the stands with West Ham beating their rivals 2-0.
And reports from inside the stadium claim a seat and other objects has been thrown at each other.
Guardian reporter Jacob Steinberg wrote on Twitter: “Fighting here. Seat thrown.”
Oliver Todd of the Daily Mail added: “Steward barriers breached at West Ham, coins everywhere, police wading in. Another bad night for the former Olympic Stadium.”
Fighting here. Seat thrown.
— Jacob Steinberg (@JacobSteinberg) October 26, 2016
Steward barriers breached at West Ham, coins everywhere, police wading in. Another bad night the former Olympic Stadium.
— Oliver Todd (@oliver_todd) October 26, 2016
West Ham’s new home ground has been plagued with trouble since opening in August.
Fans have clashed inside and outside the stadium as the east end club settle in to their new surroundings.
The visit of rivals Chelsea was seen as a potential trouble hotspot by stweards and police.
The evening appeared to be passing without incidents, until reports of trouble emerged as the 90 minutes drew closer to ending.
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