MADRID, Feb. 3 (Xinhua) -- Spanish National Police confirmed on Saturday that they have arrested 40 men who exchanged child pornography during an operation in 17 different provinces.

The police explained that they searched 42 different addresses throughout Spain, seizing portable computers, over 100 hard drives, as well as CDs and DVDs, some of which contained "extremely serious" images.

They added that some of those arrested used software to wipe discs and internet navigators in order to use a "dark web" to escape detection.