Phoenix, Jan 15 : Four people were killed and one person was critically injured when a hot air balloon crash-landed in a desert in the US state of Arizona, authorities said. According to the Eloy Police Department, the accident occurred at about 7.50 a.m.on Sunday in a rural desert area near the city, which is located about 105 km southeast of state capital Phoenix, reports Xinhua news agency. Local KNXV news channel reported that a total of 13 people -- eight skydivers, four passengers and a pilot -- were in the balloon when the tragedy happened. The skydivers exited the gondola before the crash, and witnesses told officials that the balloon was straight up and down before a hard impact, the report said. One person was pronounced dead at the scene of the crash, the other three victims died later and a fifth person is currently in critical condition in the hospital. The report also disclosed that National Transportation Safety Board (NTSB) officials said the hot air balloon crashed due to an unspecified issue with its envelope. The NTSB and the Federal Aviation Administration are investigating the accident. /IANS