Four Brazilian nationals who are suspected of being part of a "murder squad" are in garda custody tonight after officers seized a submachine gun and sawn-off shotgun as part of a major intelligence operation.
Senior sources said that the Brazilians had been hired by a Traveller gang to target the home of a man in the Arden View estate of Tullamore.
A feud in the Offaly town, that started over a €70 drugs debt, has been spiralling out of control over the past month and has now escalated to the point where innocent children could be murdered.
"Gardai have established who the target of this incident was and if a machine gun had been used indiscriminately at that property, children could have been killed," a senior source said tonight.
"This is all part of a Traveller feud that has escalated out-of-hand - it started as a row over a €70 drugs debt, then there was slagging on social media which eventually led to an extremely violent incident."
This incident cannot be outlined here for legal reasons.
The source added: "Again, this was the subject of being shared on social media and everything just got worse. Gardaí have made a number of arrests and have secured charges against a number of people but the feud is still very much active.
"And it has now reached a point where a gang of Brazilian nationals have been hired to attack the family home of one of the main protagonists in this feud."
It is understood that the arrested men are aged between their twenties and forties and have addresses in Dublin, Longford and other midlands location.
Some are understood to be illegal immigrants while others have previously worked in meat factories and fast-food outlets.
Detectives are trying to establish how the Traveller gang got involved with the Brazilians and where the deadly firearms were sourced.
The investigation began after local gardaí enlisted the force's secretive Crime and Security branch. They deployed the heavily-armed Emergency Response Unit (ERU), who made the arrests in the early hours of this morning.
"An Garda Síochána are currently engaged in an ongoing operation that has resulted from an incident that occurred in Clara," a spokesman said today.
"Four males are currently detained under section 30 of the Offences Against the State Act and a number of firearms have been recovered," he added.