Aston Villa manager Steve Bruce criticised Birmingham's decision to give their supporters cardboard clappers for the Championship derby at St Andrew's on Sunday.
Some home fans threw the clappers at Villa players including Robert Snodgrass during the 0-0 draw and Bruce was far from impressed.
Bruce, a former Birmingham boss, said: "Whoever made the ridiculous decision to have clappers here obviously doesn't know the Birmingham-Villa game as the Birmingham fans don't need a clapper. It is the last thing they need.
"But they have somehow used them as a weapon. In all seriousness someone could have been badly hurt.