Police are questioning a 16-year-old man after an incident at today's Irish Cup semi-final between Linfield and Lurgan Celtic at Windsor Park.
The teenager was arrested on suspicion of possession of a firework or flare.
He has been taken into custody for questioning.
Favourites Linfield booked a place in the final against Glenavon after overcoming the plucky underdogs 3-0. The scores were level at half-time but Aaron Burns struck three times after the break.