The premises has been evacuated and the scene is preserved. The Army Explosive Ordnance Disposal (EOD) team has been requested to attend.

These arrests form part of an ongoing garda investigation aimed at disrupting these criminal elements, gardaí said.

On Wednesday, gardaí searched a property in Bettystown.

The search operation was conducted on wasteland in Corduff as part of ongoing investigations into organised criminal activity in the Dublin 15 area.

Four men, three in their 30s and one in his 20s were arrested and are held in a Garda station in the North Western Region.

Three firearms and a large quantity of ammunition have been seized which are now subject to full ballistic examination.

This followed searches carried out at four residential properties in the Garryowen area.

The prison search is understood to be part of a garda crackdown into the activities of two rival groups involved in an ongoing feud on the south side of Limerick City.

Three men, aged in their 60s, 30s and 20s, were arrested and detained under Section 30 of the Offences Against the State Act 1939.

Garda Assistant Commissioner Justin Kelly said weapons are the lifeblood of organised crime groups

Ryan Kelly (25) was under surveillance as part of an investigation by the Garda National Drugs and Organised Crime Bureau.

Several people have been arrested in connection with the seizures

Gardai seized a battle rifle, a semi-automatic handgun and more than 40 rounds of ammunition.

In the search of the vehicle, a M1911 Handgun, G3 Rifle and 40 rounds of ammunition were seized.

Sarah Jane Byrne (35) and Jamie Moss (21) were each granted bail under strict conditions

A pistol, a submachine gun and sawn-off shotgun were found during searches on Friday

A number of licensed firearms, including at least one rifle, along with ammunition, were seized as part of the investigation

Glen Ward, 30, from Finglas, Dublin, and his brother Eric O'Driscoll, 22, also from Finglas, were arrested earlier this week and held for questioning

Anthony Walker (52), with an address at Marrowbone Lane, Dublin 8 appeared before the three-judge, non-jury court on Thursday morning.

The Keane gang are suspected of carrying out the importation of firearms and drugs on a national and international level and have been involved in a murderous feud with the McCarthy-Dundon gang since 2000, the court heard

A former member of the Defence Forces fired blank bullets from a decommissioned firearm at his wife in their home in Co Donegal, Letterkenny Circuit Court heard