Authorities in southern Mexico say two teenage sisters who went on a tour of an underground river were swept away by the current, and one has been found dead.

Guerrero state security spokesman Roberto Alvarez says the sisters, aged 16 and 19, hail from the State of Mexico.

They disappeared Saturday while on the cave tour in Cacahuamilpa National Park. Alvarez said Sunday in a statement that they were among a group of 19 visitors outfitted with life vests and accompanied by two guides.

He told The Associated Press that the lifeless body of one sister had been found. Rescuers were searching for the other.