At least 35 people died and several remain missing after a tourist boat capsized in Vietnam’s Ha Long Bay during a sudden storm.

The vessel, Wonder Seas, was carrying 53 people—mostly Vietnamese families from Hanoi—when it overturned amid hail, heavy rain, and lightning.

Ten survivors have been rescued, including a 10-year-old boy found trapped in an air pocket.

At least eight of the victims were children.

Poor weather has hampered rescue efforts, and authorities have launched an investigation.

Prime Minister Pham Minh Chinh offered condolences and vowed accountability, the BBC has reported.

Ha Long Bay is a UNESCO World Heritage site and popular tourist destination.

Written by B.C. Begley