Spanish police on Monday (November 28th) arrested four men suspected of being part of an illegal immigration ring used by the "Islamic State of Iraq and the Levant" (ISIL) to bring fighters to Europe, including those involved in last year's Paris attacks, AFP reported.

Authorities in Spain suspect the men had been in contact with "at least one" of two alleged ISIL elements arrested in Salzburg, Austria, shortly after the attacks in Paris in November 2015 that killed 130 people, the interior ministry said.

Austrian police arrested Algerian Adel Haddadi and Pakistani Mohamad Usman last December at a migrant centre in Salzburg over suspected links to the cell that carried out the attack.

Investigators believe Haddadi and Usman travelled to the Greek island of Leros on October 3rd on the same boat as two people, thought to be Iraqi, who blew themselves up outside the Stade de France stadium during the attacks.

But Haddadi and Usman were detained by Greek authorities for 25 days because they had fake Syrian passports.

The four men arrested in Spain are suspected of involvement with the ring that organised Haddadi and Usman's arrival in Europe, the interior ministry in Madrid said in a statement.

Spanish authorities are now trying to determine if the four men, whose identities were not released, were also part of ISIL.