Two Italian intelligence agents and a former member of the Israeli security forces died when a boat carrying tourists overturned in strong winds on Lake Maggiore in northern Italy.
A Russian woman was also reportedly killed when the boat, carrying more than 20 passengers, capsized on Sunday evening near Lisanza, at the southern end of the lake in northern Italy, after the weather suddenly turned stormy.
One person is still missing, officials said on Monday.
“The bodies of four people have been recovered,” fire brigade spokesman Luca Cari said.
The victims included a middle-aged Israeli man, a Russian woman and an Italian man and woman.
A rescue operation involving divers, boats and a helicopter is continuing.
News agency Ansa reported that the 16-metre boat overturned after a sudden whirlwind developed into a “small hurricane”.
Attilio Fontana, president of the Lombardy region, said that the “very serious incident” was due to bad weather.
Around 20 survivors were rescued by passing boats or swam to shore.
The passengers on the vessel included British, Italian and Israeli citizens who were reportedly on the boat for a birthday celebration.
Footage shared by local firefighters showed pieces of debris floating in the lake as a helicopter flew overhead.
The wreck was found by divers at a depth of 16 metres.
The whirlwind was part of a storm system that hit the northern region of Lombardy on Sunday evening, causing delays at Malpensa airport.
Lake Maggiore, which is on the south side of the Alps, is the second-largest lake in Italy and a popular tourist destination.