A bus carrying tourists from a cruise ship has overturned in south-eastern Mexico, killing at least 12 people, officials say.
Another 18 people were injured in the crash between Mahahual and Cafetal in Quintana Roo state.
The bus was taking 31 people, who were on a Royal Caribbean cruise, to the ancient Mayan ruin at Chaccobén.
Eight Americans died, as well as two Swedes, one Canadian, and one Mexican, Mexican media report.
Among the victims was a 78-year-old grandmother from Miami, according to US media.
Anna Behar, her 11-year-old-son Daniel, and her mother Fanya Shamis, 78, all died in the crash.
The Quintana Roo state government confirmed the dead included at least one child.
A spokeswoman for the US Department of State confirmed the death of multiple US citizens, and sent "heartfelt condolences to those affected by this tragedy".
A local driver and tour guides were also said to be on the trip.
The injured were taken to four hospitals and five people were discharged, the Costa Maya bus company said.
Royal Caribbean said it had 27 guests on the bus and described the crash as "heartbreaking".
"Our hearts go out to all those involved. We are doing all we can to care for our guests, including assisting with medical care and transportation," it said on Twitter.
We can confirm the deaths of multiple U.S. citizens in #Mexico bus accident, and several injuries. We express our heartfelt condolences to those affected by this tragedy. We are in contact w/ local authorities, have staff on scene to assist and will continue to monitor situation.— Heather Nauert (@statedeptspox) December 20, 2017
Bus crashes are common in Mexico where people often travel along dangerous routes at night - but an accident involving the deaths of so many tourists in broad daylight is rare, the BBC Mexico correspondent Will Grant says.
It is not known what caused the crash. Photographs from the scene showed the vehicle on its side with dazed survivors sitting nearby.
The driver of the bus was taken into custody, and the cause of the crash is being investigated, local media report.