The threat by dissident republican terrorists in Northern Ireland is higher than at any time since the Omagh bomb massacre almost 12 years ago, according to sources.
Police chiefs believe rival factions in the Real IRA and Continuity IRA have come together as never before to mount late night attacks on so-called prestige targets with bombs assembled in the border regions of South Armagh and North Louth.
There have been 10 attacks this year as well as the murder by the Real IRA of one of its own members, Kieran Doherty, 31, in Londonderry, where he was abducted and shot in February.
So far 64 people have been arrested and 18 charged, and up to 50 other potential incidents have been disrupted according to sources.
The threat level has been assessed as "severe" since February last year, one below "critical", the highest.
But in the aftermath of major bomb attacks outside a courthouse in Newry, Co Down, and then earlier this month at Palace Barracks, Holywood, Co Down, where the new Northern Ireland MI5 headquarters is based, senior PSNI officers fear developing technical skills, as well as increasing numbers and growing confidence, could mean the dissident capability is back to where it was in the violent run-up to the August 1998 Omagh atrocity when they blasted several towns and villages.
Former members of the Provisional IRA, opposed to the Sinn Fein peace strategy of Gerry Adams and Martin McGuinness, are suspected of involvement in preparing some of the devices, according to authoritative security sources.