Detectives from Serious Crime Branch have recovered a quantity of suspected explosives in Strabane.
The discover was made during a search at Cemetery Road on Sunday morning. It is understood the search was carried out as part of investigations into the activities of dissident republicans.
Its the second major find in the town at the weekend.
On Saturday a suspected firearm was recovered during a security alert at a house in the Ballycolman.
The gun was found in a house garden.
Army technical officers were called to the scene and four houses were evacuated while the gun was examined.
The residents, who had to leave their homes at 920am, were allowed to return at about 2pm. The gun was taken away for further examination.
Police are appealing to anyone in the area who may have saw anything suspicious in the past 24 hours.