At least four people were killed while one was injured in a hot air balloon crash in the Arizona desert on Sunday morning, according to the local police.

The hot air balloon crash landed in a rural desert area east of Sunshine Boulevard and Hanna Road and about five miles from Eloy, Arizona around 7:30am, the Eloy Police Department (EPD) revealed in an online statement.

Although the cause of the crash is yet to be known, the EPD noted that the National Transportation Safety Board (NTSB) and the Federal Aviation Administration (FAA) were on the scene and had taken over the investigation.

Tony Molinaro, a spokesperson for the FAA, confirmed that five people were on board the balloon when it crashed, Newsweek reported.

During a news conference, Eloy Mayor Micah Powell said that 13 people had gone up on the balloon, including eight skydivers who exited the gondola before the crash and were unharmed.

“What we know at this point is the skydivers were able to exit the balloon without incident and completed their planned skydiving event, and then shortly thereafter something catastrophic happened with the balloon causing it to crash to the ground,” Eloy Police Chief Byron Gwaltney said during the press conference.

One of the five remaining passengers in the gondola died at the scene, three others died at a hospital, and the fifth person remains in critical condition, Newsweek reported.

“The Eloy Police Department extends its deepest condolences to the families and friends of those involved in this heartbreaking incident,” the department said.

Eloy is a city of about 16,000 residents in Pinal County and has hosted skydiving championships and draws tourists from “countries from around the world” to Eloy, according to Powell.

He described the area as a “close-knit” skydiving community.