At least 15 Indian tourists died when a boat capsized off Vietnam's southern island of Phu Quoc on Saturday, VnExpress reported, citing local authorities.
Twenty-one people survived the accident, according to the report. The vessel was carrying 36 people, including 32 Indian tourists, three crew members and one attendant.
India's embassy in Vietnam said it was monitoring the incident and had established emergency response centres in Ho Chi Minh City and Hanoi to assist affected families.
"Exact details of the incident are being ascertained as search and rescue operations by local authorities are ongoing," the embassy said in a statement, describing the incident as "tragic."
The boat was travelling from Hon May Rut Island to An Thoi Port when it overturned about 400 m (440 yards) into the sea, according to authorities cited by VnExpress.
VnExpress reported that sea conditions were rough, with large waves in the area at the time.
Phu Quoc, Vietnam's largest island, has become one of the country's most popular tourist destination, attracting many Indian visitors in recent years.
