Fire fighters were attacked by vandals who threw stones at crews in the North overnight.
Officers were pelted with missiles as they responded to emergency calls across the east and west of Belfast. One engine was damaged.
In Lurgan, Co Armagh, a firefighter was struck on the arm by a stone but was not seriously injured.
Graham Crossett, a divisional officer at fire brigade headquarters in Belfast, said those responsible had ignored a major campaign to halt attacks on crews.
He said: "It's obvious that the message isn't getting through and the potential damage on crews and its consequences to members of the public could be disastrous.
"The worst case scenario would be a stone smashing a windscreen or hitting the driver and him losing control. This is just madness. The lives of firefighters and the public are being put at risk."
The attacks started at around 6.30pm last night and continued until 2am. Mr Crossett was unable to say whether youths were responsible, but the stoning came as the emergency services launched a new bid to crack down on children making a growing number of hoax 999 calls in Northern Ireland.
With the Easter holidays about to begin, the authorities are concerned about hoax calls rising during the break. Last year, the fire brigade saw a 20 per cent increase in such calls compared to the previous year.
PA