A dissident republican group, the Continuity IRA, has admitted responsibility for a bomb attack on a Customs and Excise post in Co Fermanagh on Sunday.
The office at Killyhevlin industrial estate outside Enniskillen was unmanned at the time of the attack, which caused minor damage.
In a statement to a local newspaper, the Continuity IRA said it regarded the office as a "Crown target".
A local UUP MLA, Mr James Cooper, called on the North's security minister, Ms Jane Kennedy, to channel every possible resource into countering the threat from dissident republicans.