Italian police arrested 17 people in a crackdown on irregular migrant and weapon trafficking on Monday.

The suspects would have partially run their illegal activities in connection with the Sicilian mafia and with a paramilitary force operating in the Balkans, according to prosecutors of Anti-Mafia District Directorate in Palermo who coordinated the operation.

All of those arrested were variously charged with transnational criminal association, migrant trafficking along the Balkan route, weapon trafficking, and jewels and money laundering, Italy's military police Carabinieri said.

The people targeted by custody warrants included nine Italian nationals from Sicily's regional capital Palermo and the northern provinces of Como and Sondrio, as well as eight people from outside of the country.

Launched in 2016, the investigation exposed two distinct operative structures within such group, according to investigators.

One was focused on favoring the entry of irregular migrants from the Balkans to Italy and Switzerland, while the second was more devoted to trafficking weapons and recycling illegal revenues derived from robberies.

The investigation was run in cooperation with the judiciary in the foreign countries of origins of the suspects, police stressed.

"Today's operation represented a relevant operative result," the chief of Carabinieri Headquarters in Palermo, Col. Antonio Di Stasio, said.

"The leaders of the criminal structure proved able to manage solid and vicious ties with Cosa Nostra (the Sicilian mob) and with dangerous subjects linked to a paramilitary group operating in the Balkan area," the official explained in a statement.

Indeed, investigators said they documented some of the suspects while holding at least three meeting with two ascertained members of the Sicilian mafia between November 2016 and October 2017.

As for the charge of weapon trafficking, police said one of the Macedonians targeted in the operation was "in possession of both short and long war weapons and some bombs, some of which have been recently sold to other subjects in the Balkans."

At least one of those subjects was currently wanted by Macedonian police for allegedly being member of a paramilitary group, the now dismantled ethnic Albanian Kosovo Liberation Army.

The paramilitary force had been involved in an armed attack in the city of Kumanovo in Macedonia in May 2015, resulting in deadly clashes with Macedonian security forces.

"Such factor (the ties with Italian mob and suspected paramilitaries in the Balkans) represented the most alarming aspect of our investigation," the Palermo Carabinieri chief stated.