New Delhi, July 20 -- A tourist boat capsized during a sudden thunderstorm in Vietnam on Saturday afternoon, leaving 34 dead and eight missing, according to state media reports.

The vessel, named Wonder Sea, was carrying 48 passengers and five crew members, all Vietnamese, on a sightseeing tour of Ha Long Bay, a popular tourist destination.

Rescue workers saved 11 people and recovered the dead near the site of the capsizing, VNExpress newspaper said. Twenty-three people remain missing.

Authorities had earlier reported that 12 people had been rescued, but later revised the figure to 11.

The boat turned upside down because of strong winds, the newspaper said. A 14-year-old boy was among the survivors, and he was rescued four hours after...