Three men have been arrested on suspicion of dissident republican activity after explosives were seized by gardai.
The men, all aged in their 30s, were detained when officers swooped on two cars on the N24 near Cahir, Co Tipperary.
Gardai said the cars and a number of explosive devices were seized.
Technical and ballistic examinations are ongoing, a spokesman said.
Gardai said officers from the special detective unit and other national and local branches of the force were involved in the operation.
The men were detained under section 30 of the Offences against the State Act 1939 at Clonmel and Cahir Garda stations.