Firefighters across Scotland attended more than 600 callouts on Guy Fawkes night, with fireworks and verbal abuse hurled at crew members.
Senior officers condemned the “mindless” actions of those who threatened fire crews at three separate incidents over the course of the evening.
The flashpoints in Glasgow, Falkirk and East Ayrshire were among 300 bonfire callouts throughout the country by 11pm.
In Glasgow, Scottish Fire and Rescue Service staff had fireworks thrown at them after attending an unsafe bonfire in the south side of the city.
No one was injured in the incident in the Govanhill area, but an investigation is now under way to track down those responsible.
The service’s deputy chief officer, Alex Clark, criticised those who put firefighters in danger.
He said: “Attacks on emergency responders are completely unacceptable and I am sure the public would be outraged by incidents where their firefighters have been targeted while working to protect people and property.
“Those responsible should know that the authorities take their mindless criminal actions extremely seriously and we work closely with police to ensure they are identified and held to account.”
In the Falkirk area, firefighters attended a callout of an out-of-control bonfire at around 6:55pm only to be threatened and verbally abused. The incident in the Larbert area left two teenage boys with minor facial injuries after gas canisters that had been thrown on the fire exploded.
Firefighters provided first aid for the youths, using the burns kit carried on the fire appliance, before paramedics arrived. One of the teenagers was taken to hospital.
The regional watch manager, Graham Cuthil, said: “It’s hard when your crew are being threatened and abused for trying to do their job and keep people safe.
“This bonfire was clearly unsafe which was sadly proven as the two young lads received burns to their faces before we could get to work and extinguish it.”
Crews also had objects thrown at them in New Cumnock, East Ayrshire, after they were called to an out-of-control rubbish fire shortly after 6:30pm.
Despite the high-profile incidents, Mr Clark said the night had been “quieter than usual” compared to previous years. He added: “Our frontline crews and operations control personnel are incredibly dedicated and their professionalism and skill were crucial to protecting communities throughout the country.
“Everyone who chose to attend an organised event this year played their part in helping to keep themselves, their families and their communities safe.”