Four men have appeared before a special sitting of the Special Criminal Court charged with firearm and explosive offences.

Joseph O'Brien, 27, with an address at 41 Cherry Orchard Heights, Enniscorthy, Co Wexford was charged with the unlawful possession of firearms and ammunition.

The charges include the unlawful possession of a Smith & Wesson .41 Magnum revolver with a filed-off serial number and over 200 rounds of ammunition. The court was told he made no reply when cautioned.

Joseph Mooney, 45, from Kilmeaden, Co Waterford was charged with possession of explosive substances, namely three mortar firing tubes.

The court was told he replied "no" when charged.

Desmond Brennan, 64, from Clonroad, Ennis was charged with possession of explosive substances, namely the possession of nitric acid, mercury and ethanol.

The court was told he made no reply when cautioned.

David Rockett, 29, from Kilmacthomas in Waterford was charged with unlawful possession of three mortar launch tubes.

The court was told he made no reply when charged.

No bail application was made.

All four were remanded in custody and will appear again the Special Criminal Court next Thursday.

A total of nine men had been arrested by gardaí as part of the investigation, four of whom have since been released without charge.

Another man remains in custody in Co Waterford.