A pilot and three other passengers were identified by authorities Monday as those killed in a hot air balloon crash in the Arizona desert over the weekend.

Eloy Police Department Chief Byron Gwaltney said eight skydivers survived the tragedy in "an empty field in a desert area" of Eloy, a city in Pinal County about 65 miles southeast of Phoenix and 55 miles northeast of Tucson, Arizona. Shortly after the skydivers completed a jump from the balloon, Gwaltney said, “something catastrophic occurred with the balloon, causing it to crash to the ground."

At a news conference, Eloy Mayor Micah Powell reported the balloon had been carrying 13 adults − its operator, four passengers and the eight skydivers. Three passengers and the pilot died, while another passenger was critically injured.

The impact, Powell said, took place in "the world's largest drop zone" for skydivers.

Eloy police identified the pilot of the hot air balloon as Cornelius Van Der Walt, 37, a resident of Eloy who was originally from South Africa. The three passengers who died were identified as Chayton Wiescholek, 28, of Union City, Michigan; Kaitlynn Bartrom, 28, of Andrews, Indiana; and Atahan Kiliccote, 24, of Cupertino, California.

The woman who was critically injured was identified by police as a 23-year-old from Scottsdale, Arizona.

"We extend our deepest condolences to the families and friends of those who have lost their lives in this tragic incident," the Eloy Police Department said in a statement.

What was the cause of the hot air balloon crash?

The cause of the crash was not immediately known Monday.

"But eyewitnesses stated that in the last several seconds of the impact that the material of the hot air balloon was just straight up and down and the impact was fairly large," Powell said.

Five people were inside the gondola when it crashed, officials said, and one died at the scene. Three passengers were taken to a hospital where they later died, Powell said.

Another passenger was taken to a trauma center and was in critical condition Sunday, Powell said.

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NTSB and FAA also investigating the fatal balloon crash

Police said the accident was under investigation by the department as well as the National Transportation and Safety Board and Federal Aviation Administration.

"While we continue our efforts, we ask for your thoughts and support for the families and loved ones affected during this difficult time," police said in a statement Sunday.

The NTSB said investigators had arrived at the scene to document the incident and examine the hot air balloon, adding that the balloon would be moved to a secure facility for further investigation.

Contributing: Abigail Celaya, Arizona Republic

Natalie Neysa Alund is a senior reporter for USA TODAY. Reach her at [email protected] and follow her on X @nataliealund.