A firecracker was set off during a Carlisle United match on Saturday.
Spectators to the Carlisle United V Notts County reported hearing a loud bang coming from the Warwick Road end of Brunton Park, 30 minutes after the first half of the game had started.
Cumbria Police tweeted on its account for Carlisle United FC: "Three males searched as a result of a firecracker in the Warwick Road end with negative result. Private message us if you can help as this could have ended in serious injury."
Spectators tweeted that the bang sounded like a bomb.
User Laura cufc said: "I was stood just in front of where it went off, it was like a bomb went off, definitely a firework and not a firecracker."
Matt Pagan tweeted: "That certainly wasn't a fire cracker. We were sat in the pioneer stand and it shook our seats."
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