Transcript for Tourist bus crashes in rural Mexico

headline at this hour. Passengers on a holiday cruise in Mexico, many of them americ Americans, crashing on a bus trip. Several dead. Tonight, members of the U.S. Mission staff are now en route to the crash site. And here's ABC's Matt Gutman. Reporter: Tonight, investigators in Mexico still trying to determine what caused this tour bus, carrying cruise passengers, to careen off the road in rural Mexico. You can see the bus on its side pushed up against that thick vegetation. Police tape is up and stretchers are there for the wounded. Bystanders appearing to rush in to help the wounded, some of whom were may haved out on the two-lane roadway. Others seeming to walk around dazed. The bus apparently went off the road on the way to the chacchoben ruins, about an hour away from where the ships docked on the yucatan peninsula, about four hours south of cancun. Its believed at least seven Americans are among the 18 people hospitalized. Some of the officials from the U.S. Embassy, perhaps our mission, are on their way there. Reporter: The royal caribbean cruise line said that it was carrying 27 passengers from its ships, "Celebrity equinox" and "Serenade of the seas". In a statement, the company said, "We are doing all we can to help our guests." David, those crew ships originated in Miami and ft. Lauderdale. And what is so gutting about this crash is that nearly half the people on that bus were killed, including a minor. David? All right, Matt Gutman, our thanks to you.

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