Italian authorities in Catania, Sicily, have launched an investigation into the disappearance of a sailor who was taking part in Operation Triton aboard Norwegian vessel Siem Pilot.
Benjamin Olafsson, 23, was last seen on Monday at 3.30 am in Catania, where Siem Pilot is docked.
Italian police are conducting a search on land and sea in close cooperation with the Norwegian police officers aboard Siem Pilot and the Norwegian National Criminal Investigation Service.
"Frontex, which coordinates Operation Triton, will take any necessary measures to support the Norwegian authorities in this difficult situation," said Frontex Executive Director Fabrice Leggeri.
Siem Pilot helped rescue 6 500 migrants in the Mediterranean since it was first deployed by Frontex in June.