A man has been charged with explosive offences and possessing terrorist documents.
Edward John Harris, from Cardiff, was arrested following reports of explosive materials being held at an address in the Ely area of the city.
Counter-terror police stressed there is no evidence of a specific terrorist threat against the Welsh capital.
He also faces four charges of possessing a document containing information useful to terrorism under section 58 of the Terrorism Act 2000.
Police said a second suspect remains in police custody for questioning.
