A man accused of threatening to carry out a Manchester Arena style attack at a football ground has been arrested.
Messages posted on Twitter spoke of shooting supporters and bombing Fratton Park, home of Portsmouth FC.
The League One side is due to face Sunderland in the second leg of a semi-final play-off later.
A 22-year-old man from Northallerton, North Yorkshire, arrested on suspicion of making threats to kill, remains in police custody.
Tweets, which have since been deleted, referenced the May 2017 Manchester Arena attack in which 23 people died.
They also referred to “Fratton Park going bang” and shooting Portsmouth fans.
Club bosses said there would be enhanced security checks at the stadium before the sold-out match.
Hampshire Constabulary said: “We continue to work with Portsmouth FC and can assure the public that a sufficient policing response will be in place for tonight’s match.”
The club has advised supporters to allow plenty of to time to get inside the stadium as enhanced security checks will be in place.
The League One play-off semi-final second leg match kicks off at 19:45 BST.