A RUSSIAN-made mortar launcher found at Dublin Port was to be brought to the north, gardaí have said.
Gardaí believe the firearm was to be delivered to a collector.
A security alert began at about 1am yesterday when customs officials stopped an eastern European-registered van in a routine check.
Officers noted that a mortar launcher was declared on documentation. When they then checked the van, they discovered the launcher.
Gardaí sealed off the area before an army bomb disposal team declared the weapon safe.
It was a decommissioned Russian-manufactured 82mm KRH 36Y launcher. There were no mortar rounds with it.
The alert ended at about 5:25am.
It is believed that it was being brought in for a private collector in Northern Ireland who had ordered it online.
Officers are liaising with the PSNI to verify this.
A woman in her twenties, who was driving the van, was arrested. She was last night being questioned at Store Street Garda station.
It is understood the woman told gardaí and customs officials that she was a courier and was driving a liveried van.
Gardaí said they were satisfied there was “no criminal intent” in importing the launcher.
"An Garda Síochána continues to investigate the importation of this firearm into this jurisdiction," a spokesman said.
