A police officer was injured and fire engine damaged after youths threw stones at them while on callouts.
Gwent Police said the incidents happened on Friday night and Saturday in the Phillipstown area of Rhymney, Caerphilly county.
Insp Andy O’Keefe said crews were called to five incidents involving arson, criminal damage and hate crime.
He said those involved had shown “complete disrespect”.
“I hope the residents of Rhymney will agree that this is not acceptable and support my team, our officers and our partners in ensuring these people are identified,” he said.
The officer suffered minor injuries and the fire engine window was cracked, he said.