Tourist bus in Mexico City were carrying passengers from a cruise ship on a highway traveling to the Mayan ruins in Eastern Mexico.

Authorities say seven American citizens and two Sweden citizens were also injured. Authorities have not yet established the nationalities of the dead, and are still undergoing investigation.

“Miami-based Royal Caribbean Cruises said in a statement that passengers from two of its ships, The Celebrity Equinox and Serenade of the Seas, were involved in the crash. The company expressed its sympathies and said it was assisting with medical care and transportation.”

U.S. authorities are working with the U.S Embassy in Mexico to determine whether U.S citizens were involved.

Video footage “from the scene shows the bus on its side in vegetation off of a two-lane highway with some of the survivors are lying on the pavement, while others walked around.”

This crash occurred about 110 miles South of Tulum, as the bus was on its way to the ruins at Chacchoben.

The bus company, Costa Maya Mahahual, that was involved, said in a statement, the bus was carrying tourists who arrived to the coastal town at Mahahual aboard a cruise ship. The company also said in addition to the tourists, there were also a guide and a driver that also aboard the bus.