Firefighters attending a fire on a railway embankment in Lurgan, Co Armagh, this week were held at gunpoint.
In a separate incident, a gun was brandished at their colleagues in Dungannon, Co Tyrone, while in Belfast and Derry fire crews were attacked with stones, bottles, petrol bombs and other missiles during street violence.
Mr Jim Barbour of the Fire Brigades Union said yesterday these attacks represent the "tip of the iceberg", and only four of 102 violent attacks suffered by crews around the North so far this month.
"It's absolutely scandalous that this sort of behaviour is continuing to go on.
"We think all right-thinking people and community leaders need to come together to condemn this," said Mr Barbour.
He said some fire crews responding to emergency calls were encircled by mobs. "The reality is many of our firefighters are still being hurt and injured when they are trying to protect the public and protect property."
The North's Chief Fire Officer, Mr John McClelland, issued a stark warning that the spiraling number of attacks on his crews could result in someone being killed.
"I don't know where it's leading, I don't know what its purpose is, but if common sense doesn't prevail serious injury will result or, worse than that, loss of life," he said.
According to Mr McClelland, none of his officers was seriously hurt during recent incidents.
However, he is seriously concerned by the incidents. "These attacks don't seem to have any clear motive other than to attack public services." Mr Sean McGlone, the sub-officer of Blue Watch at Knock Fire Station, who is from west Belfast, said the disrespect for uniformed agencies such as the fire service was once found only in republican areas of the city.
But this disregard was now evident among the youth in Protestant areas such as east Belfast.
Mr McGlone said two members of a five-strong crew at the scene of a fire were now detailed to monitor attacks and try to keep youths from tampering with appliances.
It is common for the children to hide in large numbers and then ambush a crew. "They make everything seem normal and then jump out at you," said Mr McGlone.
The fire service is seen as "fair game" because it is trying to restore normality to an area and hence is perceived to be working against "the cause" of rioters, he added.
A four-month-old appliance at his station, supplied at a cost of £250,000, was "already peppered" and just last week a crew under his command came under a hail of stones at a bonfire off the Castlereagh Road.
"Lucky enough when we entered the scene we had positioned the appliance so we could get out quickly. If we hadn't done that the appliance would have lost a windscreen.
"That would have meant that for at least one hour, east Belfast would have been without a fire engine," said Mr McGlone.
Retired fire officer Mr Eric Smyth (59), who worked the streets of Belfast from 1968 to 1977, said crews never experienced similar attacks from the public during the Troubles, when the service dealt with the aftermath of some of the worse bombing atrocities.
"The general pubic were so helpful. There was absolute control over the younger people who liked to follow the fire engines and run about them but there was no evil, no badness in them."