Mexican officials say 12 people were killed and others injured when a tour bus crashed while taking Royal Caribbean passengers on an excursion on Tuesday.
The bus, taking holidaymakers to the ancient Mayan ruin at Chaccoben, overturned on a road between Mahahual and Cafetal in Quintana Roo state in south-eastern Mexico.
Royal Caribbean issued a statement saying 27 guests from Celebrity Equinox and Serenade of the Seas were on the bus.
"Our hearts go out to all those involved in the bus accident in Costa Maya. We are doing all we can to care for our guests, including assisting with medical care and transportation," it said.
"We are working with the local authorities to learn more about the accident."
It added that no UK or Ireland nationals were involved in the incident.
A statement from the bus company said those on board were from the US, Italy, Sweden and Brazil, along with a local driver and tour guides.
Celebrity Equinox is on a seven-night Caribbean cruise that left Port Miami on December 16, with calls at Key West, Costa Maya and Cozumel in Mexico and Georgetown in Grand Cayman.
Serenade of the Seas is on a seven-night Caribbean Cruise that departed Fort Lauderdale on December 15, with calls at Key West, Roatan in Honduras and Costa Maya and Cozumel in Mexico.
