An army bomb disposal team has carried out controlled explosion on an improvised mortar bomb in Dunleer Woods, Co Louth.

It was part of last night’s operation where they spent several hours making safe a significant quantity of explosives, bomb making components, weapons and ammunition.

The area was declared safe at 11.25am today.

Gardaí investigating the activities of dissident republicans discovered a Real IRA arms and ammunition dump.

Officers from the Special Detective Unit, the Emergency Response Unit and gardaí from Louth and Meath searched the area and found a machine-gun, a bipod, a shotgun, a pipe bomb, an improvised mortar, over 100 rounds of assorted ammunition, bomb-making equipment and explosives.

The explosives and firearms were wrapped and sealed in a barrel to protect them from the elements before being buried in the ground.

Justice Minister Dermot Ahern has described the discovery as 'significant', at a time when dissident republicans pose dangers for law abiding people.

Garda Commissioner Fachtna Murphy said it is part of a determined strategy to disrupt and detect the activities of a small group who want to inflict violence and pain.

This is the second seizure of firearms and explosive material over a four-day period.

Two people have already appeared before the courts in connection with an earlier operation.

Another eight people who were arrested have all been released without charge and files are being prepared for the Director of Public Prosecutions.

Meanwhile, PSNI detectives investigating dissident republican activities arrested four men following an incident in Co Tyrone last night.

Officers from the Serious Crime Branch stopped a vehicle in the Cookstown area and found a firearm and a quantity of ammunition.

Four men were arrested and are being questioned at Antrim Police Station.