Sniffer dogs are to be used in today's derby day policing operation to prevent flares and illegal substances from being smuggled into Bramall Lane.
Police chiefs have issued a warning to fans ahead of the second Steel City derby of the season, which will see Sheffield United host Sheffield Wednesday, with the game due to kick off at 7.45pm.
Superintendent Simon Wanless tweeted: "Please don't even think of bringing any form of pyrotechnic to the ground tonight - detection dogs are out looking for you, you will be refused entry, you could be arrested, it will spoil your night out."
Fans have been advised to arrive at the ground from 6.30pm, with extra search and security checks planned.
Around 500 officers are involved in the police operation, with bobbies drafted in from neighbouring forces.