McCool was arrested at his home in Derry on Thursday.
A Derry man has appeared in court on charges linked to the New IRA.
Kieran McCool, from Ballymagowan Gardens in the Creggan area of the city, faced a number of charges when he appeared before Laganside Court in Belfast.
They include preparatory acts of terrorism, possession of explosives with intent and possession of articles likely to be of use to terrorists.
The 52-year-old had been arrested at his home on Thursday last as part of Operation Ledging, a discrete, standalone strand of Operation Arbacia, which is looking specifically at the New IRA’s bomb-making activities as well as the group’s storage of explosive devices and equipment.
McCool was remanded in custody to appear again next month.
Subscribe or register today to discover more from DonegalLive.ie
Buy the e-paper of the Donegal Democrat, Donegal People's Press, Donegal Post and Inish Times here for instant access to Donegal's premier news titles.
Keep up with the latest news from Donegal with our daily newsletter featuring the most important stories of the day delivered to your inbox every evening at 5pm.