"All recruitment has ceased. Military training has ceased. Targeting has ceased, and all intelligence rendered obsolete."
The last comments were a reference to the UVF's files on potential targets.
Spence said that armed UVF units had been deactivated and that the UVF's weapons supplies "have been put beyond reach" of rank-and-file members.
The group, which killed more people than any other Protestant group during 30 years of sectarian conflict in the British province, said its disarmament was a response to the disarmament of the Irish Republican Army (IRA), its much larger Roman Catholic counterpart.
The UVF killed more than 400 people, most of them Catholic civilians, from 1966 to 1994, when it called a ceasefire in response to a truce called by the IRA.
The latest breakthrough in Northern Ireland's 13-year-old peace process came five days before the formation of a new Catholic-Protestant government, the main goal of Northern Ireland's Good Friday peace accord of 1998.