Updated

Authorities say an illegal immigrant was shot and killed by a U.S. Border Patrol agent who was attacked with rocks in southern Arizona.

Border Patrol spokesman Omar Candelaria says the shooting occurred Monday after the agent and his dog encountered the man in an area known as "D" Hill just outside Douglas.

Authorities say the man assaulted the agent with rocks, and the unidentified agent shot back. The man, whose name also was not released, died while being transported to a hospital.

Candelaria says the agent also was taken to the hospital but was later released.

The incident is being investigated by the Cochise County Sheriff's Office, FBI and Border Patrol.