Tensions had been rising in a Limerick town for about a month before last night's violence.
Machetes were produced while a number of cars were rammed in Rathkeale, which provoked a response from the Garda Armed Support Unit.
Justice Minister Simon Harris says the scenes were 'unacceptable'.
Local journalist David Raleigh describes the background to last night's events:
A group who had previously been based in Rathkeale had left and then returend.
What sources are saying is that this group then had attempted to extort land and property from people in Rathkeale.
This has ignited a feud in the town between this group and at least two other groups in the town.