Police have warned football fans not to take fireworks, flares or smoke bombs into a stadium today.
Officers in Cleveland issued the warning as Sheffield Wednesday play Middlesborough FC at the Riverside Stadium.
An Owls supporter was arrested after he threw a flare onto the pitch when Wednesday played Queens Park Rangers in the first game of the season.
And a smoke bomb was also set off last weekend in a game between Middlesborough and Wigan.
Superintendent Mark Thornton, Cleveland Police’s match commander, said: “We have a close partnership with Middlesbrough and are taking a zero tolerance approach to anyone who attempts to take flares, fireworks or smoke bombs into the stadium.
“Fans need to consider the safety of themselves and others around them and not put people in danger by taking these items to the match.
“You have been warned - you will be dealt with robustly if you are found to be in possession of these items.”
Fans caught with any of the items will have them confiscated.
They also risk prosecution and banning orders.
The 17-year-old Owls fan, from Kilnhurst, was given a youth reprimand and banned from all Owls matches.