The Civil Guard has arrested four people officers believe might have some connection with the Islamic State and clandestine immigration routes in Europe, the Spanish Home Office said in a statement on Monday morning.

Two men were arrested in Almería (Andalusia) and another two in the towns of Arteixo and Tufions-Vimianzo (Galicia).

The Home Office did not specify the nationality, ages or gender of the four, or what charges they had been arrested on, but said they were “linked to an irregular immigration network that could have been used by the Islamic State”.

A spokesman for The Civil Guard told The Spain Report at least three were men and that all four were of North African origin: "The two in Galicia are Moroccan and the two in Almería are Algerian".

He could not say either what specific charges the four had been arrested on.

The network the men are suspected of “having maintained contact with” is the “so-called ‘Syrian refugee route’ between Turkey and Eastern Europe”.

“That would be the same set up used in October 2015 by several members of the Islamic State to enter Europe, along with the authors of the Paris attacks in November last year”, said the statement.

The Home Office said the four North Africans arrested today in Spain are thought to have been in contact with one of the two men arrested in Austria in connection with the Paris attacks in November 2015 which killed 90 people near the Stade de France, at the Bataclan theatre and at nearby restaurants.

In July, Austria extradited "29-year-old Algerian Adel H. and the 35-year-old Pakistani Mohamad U", who were in possession of fake Syrian passports, to France, where they were charged with “criminal conspiracy with terrorists”.

Civil Guard intelligence officers are working on the case under the direction of investigating court number two at the National High Court in Madrid.

Spain says it has now arrested 168 “jihadi terrorists” since raising the anti-terror threat level to four (out of a total of five) in June 2015, although authorities provide little information on the outcome of the arrests or their passage through the judicial system.