At least 37 people have been confirmed dead after a boat carrying tourists on a sightseeing excursion capsized during a sudden thunderstorm in Vietnam on Saturday afternoon, according to a local news report by the VNExpress newspaper.

The Wonder Sea boat was carrying 48 passengers and five crew members, all of them Vietnamese, during a tour of Ha Long Bay, a popular destination for visitors, according to the reports.

Rescue workers saved 11 people and recovered the bodies of the deceased near the site of the capsize, the newspaper said. So far, five people are still missing.

A 14-year-old boy was among the survivors. He was rescued four hours after being trapped in the overturned hull.

According to the newspaper, the tourist boat was pulled ashore early Sunday, with the bodies of three crew members discovered inside.

The newspaper said that most of the passengers were tourists, including about 20 children, from Hanoi, the country's capital.

The boat capsized due to strong winds. A tropical storm is also moving toward the area. A national weather forecast said that Storm Wipha is expected to hit Vietnam's northern region, including the coast of Ha Long Bay next week.

(With input from AP)