Multiple authorities, including the Coast Guard, were reportedly searching for the four Italian crew members and the Tunisian sailor missing from the Franco P tugboat, which was complicated by high winds.
“Searches have been going on since last night and they encompass a very large area – about 90 [square] miles – in a stretch of sea located between Italian, Croatian and Albanian waters,” Vincenzo Leone, captain of the Direzione Marittima della Puglia (Puglia’s coastguard), said via Repubblica.
The captain of the vessel was the only individual who was confirmed to have survived after being rescued from the sea by a nearby Croatian boat.
The Franco P issued an alert to port authorities that it was sinking in an area located about 50 miles of the coast of Bari in southern Italy Wednesday (May 18) night.
The vessel was pulling a pontoon and traveling from ports of Ancona to Dures at the time of the accident.
The pontoon was carrying 11 people, all of whom were rescued, as it remained adrift after the tugboat accident took place.
Authorities hadn't confirmed what caused the tugboat to capsize as of Thursday morning.