At least 12 foreigners, most of them believed to be from the United States, died when a bus plunged down a steep cliff in northern Chile, Cooperativa radio station reported.

Cooperativa quoted city council chief Juan Carlos Poli in the northern city of Arica as saying that the tourists were from the Celebrity Cruises’ ship Millennium, which was docked in Arica.

At least four other tourists were injured in the accident, which happened near the Chile-Bolivia border on an excursion to a national park.

“It’s a very dangerous slope, a driver without experience would have an accident if he did not come down very carefully... It’s very steep,” Rafael Caro, manager of a tour company associated with the cruise, told Cooperativa.

Celebrity Cruises is a unit of Royal Caribbean Cruises, the world’s second largest cruise group.

Chilean police look at the bus accident,north of santiago.