The RUC have said that 415 pounds of home-made explosives found in the search of a flat in a loyalist area of North Belfast was linked to the Ulster Volunteer Force.
The explosives were found in the new Mossley estate.
As RUC men were recovering the haul, they were attacked with a blast bomb but there were no serious injuries.
The massive haul has raised serious concerns as the UVF is supposed to be on ceasefire.