Firefighters came under attack in County Armagh and Belfast at Halloween as crews responded to more than 130 call-outs on Tuesday night.
Many incidents were bonfire-related.
Crews were targeted in Keady, Crossmaglen and Armagh city. No-one was injured but a fire appliance was slightly damaged in the Keady attack.
In Belfast, police were called to the Holylands after a large crowd gathered and a fire was lit on the street shortly before 03:00 GMT on Tuesday.
'Disruptive and reckless'
A spokeswoman for the Northern Ireland Fire and Rescue Service said the attacks on its crews were carried out by "youths throwing bottles and small bricks".
She added that seven crews were called out to hoax incidents on Halloween.
Overall, firefighters dealt with 136 incidents on Tuesday night - an 18% decrease on the same period last year.
Police said that between 19:00 GMT and midnight, PSNI contact centres received almost 3,000 calls.
They said that figure was "up on the usual 1,500 - 2,000 we normally get on a weekday".
When officers arrived to deal with the Holylands disturbances in the early hours of Tuesday, they found that a mattress had been set on fire on Agincourt Avenue and called firefighters.
The crowd dispersed within a short time, but Insp Duncan McBain issued a warning about the consequences of anti-social behaviour.
"Police would ask young people celebrating Halloween to respect residents in the area," he said.
"They are reminded that their actions can often become both disruptive and reckless, and those involved also run the risk of ending up with a criminal record."