A suspected "hit team" from South America is being quizzed by gardai in the midlands.
Officers from the elite Emergency Response Unit swooped on four men, believed to be Brazilians, early, on Wednesday morning near Clara, Co Offaly.
Three heavily armed men were in a van with a fourth in a car. They had a machine-gun, sawn-off shotgun, and several rounds of ammunition.
A source said: "This is something new. A suspected hit team from South America.
One lineof enquiry is that they were hired by a gang of criminal Travellers to shoot a rival. “It’s not known who the intended target was. But it does point towards a Traveller feud.
“It’s related to gang feuds in the midlands and not connected to the Kinahan-Hutch or other Dublin-based feuds.”
It’s understood officers from the secretive Security and Intelligence unit, tasked with security of the State and investigating subversive or terror-related crime, had been monitoring the ‘hit squad’.
Security and Intelligence, based in Garda HQ at the Phoenix Park, has replaced the old Crime and Security branch and is most secretive arm of the force.
One source said: "These officers work for what is essentially Ireland’s security service. They have access to all manner of sophisticated equipment.”
The four South Americans are being held in garda stations in Tullamore, Co Offaly, and Portlaoise, Co Laois, under Section 30 of the Offences Against the State Act and can be held for up to three days.
Although the arrests are not believed to be connected to any Dublin feuds, follow up searches were carried out in the capital.
A garda spokesman said: “An Garda Siochana are currently engaged in an ongoing operation that has resulted from an incident that occurred in Clara, this morning, Wednesday 27 May 2020.
“Four males are currently detained under section 30 Offences Against the State Act and a number of firearms have been recovered.
“This is an ongoing operation and An Garda Siochana has no further comment at this time.”
