Fireworks have been hurled at police officers in Sheffield.
Yobs have targeted members of the Central local policing team in Broomhall twice this week.
South Yorkshire Police said residents have also been targeted.
Officers investigating the incidents want to hear from anyone with information on those responsible.
They also want information on where the yobs are stashing their fireworks.
A South Yorkshire Police spokesman said: "Officers have been targeted for the second night in the Broomhall area of Sheffield. Luckily there have been no injuries but of course there is very serious potential if anyone is hit.
"Local residents are also having fireworks thrown at them.
"Any information to lead us to the offenders or location of stashed fireworks is greatly received."
Call South Yorkshire Police on 101.