The pilot of a hot-air balloon that caught fire in mid-air and crashed, killing 19 tourists, jumped from the gondola without shutting off the gas valve, Egyptian Civil Aviation Minister Wael al-Maadawi said.
A Briton also managed to escape from the balloon by leaping to safety before it soared into the sky and exploded in a fireball, Maadawi said, according to the state-run Ahram Gate website.
The blast came during an early-morning tour over the famed pharaonic sites in the southern Egyptian city of Luxor.
The incident cast a pall over Egypt's tourism industry, which is struggling to rebound two years after the uprising that ousted Hosni Mubarak, with officials seeking to deflect potential criticism about regulatory oversight in the sector and across the nation.
Maadawi said the company that operated the flight was licensed, as was the pilot and the balloon itself, and necessary inspections were up to date.
In some of the first details to emerge about the incident, Maadawi said that after the fire broke out, the pilot jumped from the balloon when it was five metres above the ground without turning off the gas.
With the reduced weight, the balloon shot up again "with the passengers, while it was burning", he said.
The 19 dead comprised nine from Hong Kong, four from Japan, three from Britain and two from France, according to Egyptian health officials.
Amateur video footage aired by al-Jazeera showed the balloon soaring in its final moments, smoke streaming from the gondola, before it deflated and plummeted in a fireball.
Egyptians on another balloon are heard commenting in horror and appealing to God.
Maadawi said Egypt had agreed to a UK request for a British investigator to monitor the crash inquiry.
The incident increased concerns in Egypt's tourism industry, particularly in Luxor, where tourists have been driven away in the past, particularly after a 1997 militant attack that left more than 50 tourists dead.
Egyptian Airports Company head Gad al-Kareem Nasr said there were "no negative repercussions on tourism and aviation in domestic airports" especially since criminal motives are not suspected in the incident, the state-run Middle East News Agency reported.
Balloon flights have been grounded in Luxor for three days pending the investigation.
The unrest gripping the nation, including flare-ups of violence that left more than 50 dead last month amid demonstrations against President Mohammed Mursi, has caused a drop in tourists, especially from Europe and North America, said Amr Abdel-Ghany, a pilot at Luxor-based Hod Hod Soliman, one of the local companies that offers hot-air balloon rides.
"The situation has deteriorated more with the Islamist government and the rise of Islamists issuing fanatical edicts against tourism and alcohol," Abdel-Ghany said.
"I mean, who would want to visit a country with such a messed up security and political situation?"