Moran, who absconded from his trial for armed robbery in 2009, was detained in the town of Calpe on the Costa Blanca, according to a Spanish police statement, which described the Briton as "a dangerous fugitive".
It did not specify when he was apprehended but it said that Moran "again attempted to flee and violently resisted the officers".
"The detainee is one of the most wanted British criminals on the run in our country," the statement added.
During a search of the home of Moran's partner in Calpe, a town popular with expatriates, police said they discovered two handguns as well as ammunition.
Last November, Moran evaded another attempt to arrest him by shaking off Spanish police officers in a car chase.