GARDAÍ AND PSNI officers investigating Tuesday's drugs and firearms seizure were last night questioning four men following the arrest of two further suspects yesterday.
The latest arrests came as Fine Gael strongly criticised security in Irish prisons after Garda sources named an inmate who they said they suspected of organising the drugs and guns shipment via a smuggled mobile phone from his cell.
Fine Gael's spokesman on justice Charlie Flanagan TD said the alleged involvement of the prisoner in sourcing from the Netherlands 41 guns and heroin and cannabis valued at €4.2 million suggested security in jails was an "abject failure".
He said despite promises from the previous minister for justice Brian Lenihan that technology to block mobile phone signals in jails was being piloted it now appeared the pilot scheme "has not even started".
"The finger of blame for this scandal points in only one direction - justice Minister Dermot Ahern. He is presiding over the black hole in prison security, and has given no indication of how he plans to stop gang lords from conducting their operations from their prison cells."
Mr Flanagan said airport-style security was needed in every prison, including scanners and sniffer dogs, along with tougher screening procedures to prevent phones and contraband being smuggled to inmates.
Garda sources have named a prisoner, a one-time associate of John Gilligan, who they believe organised the drugs and guns shipment from the Netherlands to Dublin via Northern Ireland.
Tuesday's seizure came about after a four-month investigation, codenamed Operation Bench, involving customs and police services in the Republic, Northern Ireland and the Netherlands.
A Dublin man, aged 34, was arrested with 14 firearms in a Belfast hotel on Tuesday afternoon. He is a close associate of the inmate who is believed to be at the head of the smuggling gang.
A second man, aged 42 and from Borrisokane, Co Tipperary, was arrested at the same time on Tuesday in Dublin with an estimated €4.2 million of drugs and 27 firearms.
A large Garda team stopped the man's car near the Coachman's Inn beside Dublin airport. It is believed he was bringing the haul from Belfast for delivery to crime gangs in Dublin and Limerick.
The guns found in Belfast were believed to have been destined for Northern Irish gangs.
Both of the men arrested on Tuesday were still being questioned last night in Belfast and Blanchardstown, Dublin.
A follow-up operation yesterday in the Republic resulted in two further arrests. The men were arrested in Birr, Co Offaly, and Roscrea, Co Tipperary. They are both in their 30s.
They were taken to Blanchardstown Garda station for questioning, and were still being detained last night.
Garda sources said the men were involved in the "logistics" of the attempted smuggling operation.
The same sources said the man arrested in Belfast was the most significant figure of the four arrested so far.
