At least 37 people died after a tourist boat capsized at Ha Long Bay, a popular tourist destination in northeast Vietnam.

The"Wonder Sea" vessel, which was carrying 48 passengers and five crew members, was hit by a storm on the evening of Jul. 19 and capsized due to the thunderstorm.

Out of the 48 passengers, 20 were children, according to local news site VNExpress. The oldest passenger was 53-year-old and the youngest was three.

Most passengers were reportedly families from Hanoi.

No official announcement has been made on the nationalities of the tourists.

Local news site VNExpress reported that 11 have been rescued, with rescue teams searching for the remaining five who are missing.

Out of the 11 rescued passengers, one succumbed to injuries in the hospital, VNExpress reported.

300 rescuers, including over 20 special forces divers, were deployed and they searched through the night for victims.

The"Wonder Sea" had set sail at 12:55pm on Jul. 19 for a sightseeing tour along Ha Long Bay.

The boat was to tour around different islands in the bay before making its return the following afternoon.

Less than an hour into its journey, the boat was hit by a storm and capsized.

Unfavourable weather is expected in the upcoming days as Typhoon Wipha heads towards northern Vietnam.

Ha Long Bay, a UNESCO World Heritage Site known for its blue-green waters and limestone islands, attracts tens of thousands of visitors every year.