G7 interior ministers brainstormed on Friday on how to tackle one of the biggest security threats facing the West, as the EU promised to help close a migration route labelled a potential back door for terrorists.
The group kicked off its first working session in a seafront hotel on the island of Ischia on how to deal with the potential return to Europe of foreign fighters fleeing a crumbling Islamic State group.
Italian Interior Minister Marco Minniti warned last week that jihadists planning revenge attacks on Europe following a decisive IS defeat in Syria could hitch lifts back to Europe on migrant boats from Libya.
EU President Donald Tusk said on Thursday that the bloc would offer "stronger support for Italy's work with the Libyan authorities", and there was "a real chance of closing the central Mediterranean route".
Italy has played a major role in training Libya's coastguard to stop human trafficking in its territorial waters, as well as making controversial deals with Libyan militias to stop migrants from setting off.
The numbers of migrant departures from the crisis-hit country have dropped 20% so far this year.
Italy said on Wednesday the group would also be working on how to go about "de-radicalising" citizens returning from the IS frontline to prevent them becoming security risks in jails.
France said there would be negotiations on tackling the legal headache of prosecuting returnees, with questions over what sort of evidence, collected by whom, could be used in a domestic court.
Tens of thousands of citizens from Western countries travelled to Syria and Iraq to fight for IS between 2014 and 2016, including some who then returned and staged attacks that claimed dozens of lives.
The ministers of the Group of Seven --- Britain, Canada, France, Germany, Italy, Japan and the US -- will spend their second working session on the island off Naples on the thorny issue of terrorism online.