MEXICO CITY: A bus carrying tourists from US cruise ships to an archeological site in Mexico crashed Tuesday after running off the road, killing at least 12 people including several foreigners, state authorities said.

The crash, which left another 18 injured, happened on a highway in the state of Quintana Roo, located on the eastern tip of the Yucatan Peninsula and well known as home to the Caribbean resort city of Cancun.

The dead and injured included "citizens of the United States, Sweden and Brazil," a brief statement said without further information on numbers from each country, or their ages.

The bus was carrying 31 passengers on a straight stretch of road with little traffic. The cause of the accident was not immediately known.

Twenty-three of the passengers had arrived on the ships Celebrity Equinox and Serenade of the Seas, cruise owner Royal Caribbean Cruises told AFP.

Mexican authorities said that they did not have further details of the nationalities of those killed.

A civil defense source told AFP privately however that most of the dead were Americans. Among the injured were eight Americans, three Brazilian and two Swedes, the source added.

The bus was headed for a resort town called Mahahual that features archeological ruins.

Quintana Roo is the Mexican state that receives the greatest number of international visitors, with many headed for Cancun's beaches and legendary Maya ruins. —AFP