(Reuters) - A tourist helicopter crashed in the United States’ Grand Canyon on Saturday, killing three people and injuring four others, Arizona media and a federal aviation spokesman said.

The helicopter was on a tour of the canyon, one of the top U.S. tourist destinations and more than a mile (1.6 km) deep, when it went down, a dispatcher for the Hualapai Department of Emergency Services told Phoenix television station KNXV.

He said three people were killed and four had unknown injuries, and that authorities were possibly looking for one or two more people, the station reported.

The Hualapai Department of Emergency Services directed calls to police, who did not respond immediately to a request for comment.

The helicopter, an Eurocopter EC130 from Airbus, “crashed under unknown circumstances in the Grand Canyon” and suffered substantial damage, Allen Kenitzer, a spokesman for the Federal Aviation Administration, said in an email.

“Local authorities say that at least seven people were on board the helicopter,” he said. The Federal Aviation Administration and the National Transportation Safety Board will investigate, Kenitzer said.