(CNN) — (CNN) Fourteen tourists on a hot air balloon ride in southern Egypt were killed Tuesday when the balloon exploded and plummeted to the ground, authorities said.
It was the deadliest hot air balloon accident in the world in at least 20 years.
Twenty-one people were in the balloon when it dropped about 300 meters (almost 1,000 feet) in the city of Luxor, the Egyptian interior ministry said.
A gas explosion caused the crash, state-run EgyNews reported.
Earlier, the agency said 19 tourists had been killed but later revised that number down to 14.
Passengers in the balloon included 19 foreign tourists: nine from Hong Kong, four from Japan, three from Britain, two from France and one from Hungary, officials said.
An Egyptian pilot and another Egyptian were also on board, Luxor province spokesman Badawi al-Masri said.
Three people -- two Britons and an Egyptian -- are hospitalized, and four passengers remain missing.
Balloon rides offering panoramic aerial views of the Nile River and the ancient temples of Karnak and Hatshepsut are a popular tourist attraction in Luxor, about nine hours' drive southeast of Cairo.
"You can see Valley of the Kings in the background bordered by farmland," Pauline Liang of Vancouver, Canada, told CNN's iReport last year. "Below were banana farms, and behind us was the city of Luxor. There was a great contrast between desert landscape, lush farmland and urban development."
The last hot air balloon accident in Luxor occurred in 2009, when 16 foreign tourists were injured after a balloon struck a cell phone transmission tower.
Until Tuesday's incident, the deadliest accident in recent memory took place in 1989, when 13 people were killed after two hot air balloons collided in Australia.
Egyptian government spokesman Alaa Hadidi announced the Cabinet will form a committee from the Ministry of Civil Aviation to investigate the cause of Tuesday's accident, EgyNews said.