Two Derry men arrested by gardai after the interception of a partly-prepared bomb near the Border in Co Donegal are due to appear before the Special Criminal Court in Dublin charged with possession of explosives.
Meanwhile, the Garda and RUC are significantly stepping up security arrangements in preparation for a possible outbreak of violence as the deadline set for political agreement in the North and the confrontation over Drumcree approach.
The RUC has been steadily building up its Mobile Support Units (formerly the riot squad) in all divisions in preparation for possible widespread disorder.
These Divisional Mobile Support Units (DMSUs), which are at the fore in confronting both loyalist and republican street disorder, have been tripled in strength in some divisions.
The Garda has also been stepping up patrolling and detective work in the Border area, and this is being further heightened following Thursday's seizure of the bomb in Donegal.
There are concerns among both forces about a possible deterioration in the security situation in the North if the political parties and the governments fail to reach agreement by the June 30th deadline. There are fears of violence from dissident terrorist groups on both sides of the political divide.
Gardai were yesterday still trying to decide which group was planning to use the bomb which was being transported across the Border on the road between Letterkenny and Derry when it was stopped by two traffic officers. The officers became suspicious of the Northern-registered Ford Escort and stopped it.
It is understood the gardai had prior information about an intended bomb attack which could have coincided with the beginning of the loyalists' Long March from Derry to Drumcree which started on Thursday afternoon.
Senior security sources on both sides of the Border said that as the march proceeds tension will inevitably increase, especially in the event of a failure to secure a political agreement. The fear is that dissident terrorist elements from either side, who wish to damage the process, will seek to cause instability through a bomb or gun attack.
On the republican dissident side, it is known that members of the group known as the Continuity IRA in Belfast and Derry have split from their former leadership in the Republic after rows which have been going on for almost a year.
There are suspicions that the former Continuity IRA group in Derry, which includes a number of former Provisional IRA members, was behind the attempt to bring the 300lb bomb, intercepted by the gardai, across the Border to coincide with the start of the loyalist Long March".
One of the men being questioned by gardai in Letterkenny about the bomb is known to have had connections with the Provisional IRA, while the other is not known to have had any previous terrorist connections. Both are from Derry and in their 20s.