A rock slide in a cave Sunday killed two people and seriously injured two others in the Perm Territory in the Urals, Russian authorities said.

Five speleologists, or cave experts, were more than a mile deep in the cave when the collapse occurred. One person managed to escape and notify rescuers, RIA Novosti reported.

One of the speleologists was hospitalized with brain injuries. The injuries of the second person had yet to be fully assessed, RIA Novosti said.