Three people with suspected links to the "Real IRA" were still being questioned today by detectives in Derry today.
The three, two men and a woman, were held yesterday after what police called a major security operation close to the border. The arrests were made after police stopped a car on the outskirts of Derry city. Two handguns were found in the vehicle.
Later another man was picked up for questioning in Strabane, Co Tyrone, after a number of searches in that area.