An Algerian national wanted by Belgium was arrested in Italy on Saturday, AFP reports, citing local media.
The suspect is wanted over a probe into fake ID documents used by the Paris and Brussels attackers, the news agency said.
He was named as Djamal Eddine Ouali, 40, and was detained under a European arrest warrant in the southern region of Salerno.
Ouali was arrested in the southwestern town of Bellizzi as part of a joint operation between anti-terrorist forces and Rome's special operations police, local security forces said.
He was suspected of being part of a criminal network that produced fake documents for illegal immigration, the AGI news agency reported, adding the alleged accomplice of the Brussels attackers would be extradited to Belgium in the coming days.
Arrests have continued in Europe following last week’s attacks in Brussels. On Friday, French police arrested 34-year-old Reda Kriket in Paris, and accused him of being in the advanced stages of planning an attack and having ties to Abdelhamid Abaaoud, the suspected ringleader of the November 13 terror attacks in Paris, who was killed in a raid shortly after the attacks.
In addition, three men were arrested on Friday in Brussels for links to Kriket's alleged plot.
As for Ouali, AFP said, suspicions were raised after local immigration officials checked his residency permit. Police had been searching for a man with the same name and belonging to the same organization since January 6.
Hundreds of digital photographs were then seized from a counterfeiter's workshop, including three of those who planned the deadly attacks in Paris in November.
One of those photographed was Najim Laachraoui, a suicide bomber at Brussels airport, reports quoted police as saying.
Investigations are ongoing as to how Ouali came to be in Italy and into the networks of which he may have been a part.