A man has been arrested after threats were put on social media about tonight's League One play-off semi-final second leg with Sunderland at Fratton Park (Thursday 16 May).
Hampshire Police said the 22 year-old man from North Allterton was arrested in the early hours of Thursday morning on suspicion of making threats to kill.
It follows threats posted on social media about the match, and the club said it was working with police on the matter.
The club said there will be enhanced security checks rolled out ahead of the match, and it is advising fans to arrive in plenty of time to make sure they are inside the stadium for the start of the game.
In a statement Hampshire Police said:
"We are aware of threats made on social media regarding the football match between Sunderland and Portsmouth taking place in Portsmouth tomorrow, (Thursday).
"We are looking into these posts and want to assure the public that a sufficient policing response will be in place for the match tomorrow and that we are working alongside Portsmouth FC."
Tickets for the match have sold out, and kick off is at 7.45.