More than 20 people are missing or unaccounted for following a flash flood in Grand Canyon National Park in the US state of Arizona, authorities said on Sunday. Rescue teams have so far evacuated 62 people.

The "significant flash-flood event" occurred on Saturday in Bright Angel Canyon and the Phantom Ranch area, the US National Park Service said in a news release. It urged anyone who knew of hikers or backpackers who were in the inner canyon along the Bright Angel Creek corridor on Saturday, as well as anyone with a campground reservation in the affected area, to provide information to the National Park Service Investigative Services Branch.

Park officials said they were continuing evacuation and response efforts in coordination with the Arizona Department of Public Safety while working to account for people who may have been in the affected areas.