MADRID, Dec. 17 (Xinhua) -- Two suspected extremist sympathizers were detained on Monday in separate operations in different parts of Spain, the Spanish Interior Ministry confirmed.

The Mossos D'Esquadra (Catalan regional police) detained a man named Khalia Makran who is of Dutch origin, in an operation close to the city of Tarragona (northeast Spain).

The police had been looking for Makran following the discovery of pro-extremist messages he had painted on the wall of the hotel bedroom where he had been staying at the nearby town of Vilaseca.

The second arrest took place in the town of Vitoria, northern Spain, with the detainee described as a 36-year-old Algerian man who is suspected of working to recruit for the Islamic State (IS).

The suspect used his position as president of a cultural association to distribute extremist propaganda. The Interior Ministry said that he had told associates it was "very easy" to make home-made bombs and he had been attempting to recruit fighters.

The ministry added that he had previously shown a "violent attitude" towards the police, on one occasion waving a knife and shouting "I am going to kill policemen," and on another "attempting to assault" a pair of police officers on duty.

Spain has been on a level 4 of alert (on a scale of 1 to 5) against a possible terror attack since 2015.