The interior ministers of the Group of Seven (G7) industrialized nations gathered Thursday on Italy's Ischia island facing the Gulf of Naples ahead of a security and counter-terrorism summit on Friday.

The agenda will focus on preventing extremist propaganda and recruitment on the internet and combating foreign fighters, or radicalized Europeans who joined the ranks of so-called Islamic State (ISIS) in Iraq and Syria, Italy's Interior Ministry said in a statement.

Foreign fighters are expected to try to return to Europe, where they could pose a threat to their EU home countries, as ISIS has been largely defeated in Syria and Iraq.

The foreign fighters are often radicalized and recruited on the internet, which is why executives from leading social media companies have also been invited to Ischia.

The summit chaired by Italian Interior Minister Marco Minniti includes the interior ministers of Canada, France, Germany, Japan, the UK and the US, plus EU Migration Commissioner Dimitris Avramopoulos, EU Security Commissioner Julian King, Interpol Secretary General Jurgen Stock.

Also present will be Facebook Counter-terrorism Policy executive Brian Fishman, Google VP for Public Policy Nicklas Lundblad, Microsoft VP for EU Government Affairs John Frank, and Twitter Public Policy exec Nick Pickles.

The summit begins early Friday morning and ends in the early afternoon.