Police have confirmed there is "no wider risk to the public" after emergency services responded to an incident in a park.
A witness described seeing "at least four" police cars and numerous ambulances at Wild Park, in Brighton, at around 3pm.
The witness saw specialist paramedic vehicles, including Land Rovers, while driving along Lewes Road this afternoon.
Sussex Police say they were called to Wild Park in Brighton shortly after 2pm this afternoon, to concerns for a person's welfare.
The spokesman added: "They were treated by the ambulance service.
No further information is available at this time, but there is not considered to be any wider risk to the public."
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Wild park is the largest local nature reserve in Brighton, with many paths and walks across 593 acres of green space.
The park spans between Coldean, Hollingdean and Moulescoomb.
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