The PSNI and An Garda Síochána have conducted searches on the Derry-Donegal border today in relation to New IRA activities.
A PSNI statement did not however indicate whether any items were recovered.
A spokesperson for the PSNI said: "Detectives from the PSNI's Terrorism Investigation Unit, with support from An Garda Síochána, have conducted a search of land at Killea Reservoir on the border of Derry and Donegal as part of an ongoing investigation into the activities of the New IRA.
Derry City and Strabane Area Coordinator Chief Superintendent Darrin Jones said: "The search operation today covered a large area of land at the Reservoir and officers from the Police Service were supported by colleagues from An Garda Síochána.
"Today's action is part of our ongoing investigation into the activities of the New IRA."
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