At least two people have died after a boat carrying more than 20 passengers, including tourists, sank in strong winds on Lake Maggiore in northern Italy, local media say, Report informs, citing BBC.
Two others are missing, according to reports.
The boat overturned on Sunday evening between the towns of Sesto Calende and Arona, Italian media say.
Italy's fire service said 19 people were safe but their search continued for those reported missing.
Attilio Fontana, president of the Lombardy region, said the "very serious incident" was due to bad weather.
The boat was 16m (52ft) long and had been hired by tourists, he said on Facebook.
According to news site La Repubblica, the boat had been carrying 25 people who were celebrating a birthday when it capsized and sank soon afterwards.
Everyone onboard went into the water - but many of the passengers swam ashore or were rescued by other boats, other Italian media outlets reported.
Rescue divers and a helicopter have been scrambled to help with the search at the lake's southern end, and several ambulances and an air ambulance attended the scene.
A video shared by firefighters showed chairs and other debris floating in choppy waters.
Lake Maggiore - on the south side of the Alps - is shared by Italy and Switzerland, and is a popular destination for tourists.
The area has seen poor weather over the last day, with Italy's meteorological service issuing thunderstorm warnings.