A man has reportedly been arrested after a bomb threat was made against Portsmouth's League One play-off semi-final second leg with Sunderland on Thursday night.
On Wednesday, a social media user threatened to shoot and bomb supporters attending the game at Fratton Park.
Threats, posted on the Twitter account of @Kieran30971361, referenced the Manchester Arena bombing which killed 23 people in May 2017.
'I wounder (sic) how many Portsmouth fans I can shoot everyone remember the Manchester arena bombing just imagine fratton park going bang well let's find out tomorrow,' read the initial post.
It was followed by: 'Bomb bomb fratton park went bang the Portsmouth fans all died Haha going to be fun tomorrow headline news.'
Twitter user @CookiePFC- posted: '20 quid to anyone who can hit a family of Sunderland fans in the away end with a smoke bomb Thursday'.
An earlier post from a Portsmouth fan encouraged home fans to throw smoke bombs at away supporters.
A Hampshire Police statement on Thursday morning said: 'A man was arrested overnight after threats were put out on social media about tonight's Portsmouth v Sunderland game at Fratton Park.
'The 22-year-old man, from Northallerton, was arrested in the early hours of this morning on suspicion of making threats to kill. He currently remains in custody.
'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.'
Hampshire Constabulary said it was looking into the threats.
'We are aware of threats made on social media regarding the football match between Sunderland and Portsmouth taking place in Portsmouth tomorrow,' read a police statement.
'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.'
Sunderland lead the tie 1-0 following Saturday's first leg at the Stadium of Light.