LUXOR, Egypt — The terror lasted less than two minutes: Smoke poured from a hot air balloon carrying sightseers on a sunrise flight over the ancient city of Luxor, it burst in a flash of flame, and then plummeted about 1,000 feet. A farmer watched helplessly as tourists trying to escape the blazing gondola leaped to their deaths.
Nineteen people were killed Tuesday in what appeared to be the deadliest hot air ballooning accident on record. A British tourist and the Egyptian pilot, who was badly burned, were the sole survivors.
The tragedy raised worries of another blow to the nation’s vital tourism industry, decimated by two years of unrest since the 2011 revolution that toppled autocrat Hosni Mubarak. Luxor has been hit hard, with vacant hotel rooms and empty cruise ships.
It also prompted accusations that authorities have let safety standards decline amid political turmoil and infighting, although civil aviation officials said the balloon had been inspected recently and that the pilot may have been to blame, jumping out rather than stopping the fire.
Authorities suspended hot air balloon flights, a popular tourist activity, while investigators determined the cause.
The balloon was carrying 20 tourists — from France, Britain, Belgium, Japan, and Hong Kong — and the pilot on a flight over Luxor, 320 miles south of Cairo, officials said. The flights provide spectacular views of the ancient Karnak and Luxor temples and the Valley of the Kings, the burial ground of Tutankhamun and other pharaohs.
According to initial indications, the balloon was in the process of landing after 7 a.m. when a cable got caught around a helium tube and a fire erupted, according to an investigator.
The fire detonated a gas canister and the balloon plunged about 1,000 feet to the ground, crashing in a sugar cane field just west of Luxor, a security official said.
Both the investigator and the security official spoke on condition of anonymity.
‘‘I saw tourists catching fire and they were jumping from the balloon,’’ said Hassan Abdel-Rasoul, a farmer. “They were trying to flee the fire but it was on their bodies.”
One of those on fire was visibly pregnant, he said.
Amateur video from another balloon showed the balloon’s final moments.
Smoke is seen rising for several seconds from the gondola, silhouetted against the sun. The balloon catches fire with a flash, and in an instant, it bursts and falls as a fireball to the ground, trailing smoke. Egyptians on the balloon filming the scene can be heard crying and gasping in horror.
The crash immediately killed 18, according to Governor Ezzat Saad. Two Britons and the pilot were taken to a hospital, but one died.
Among the dead were nine tourists from Hong Kong, four Japanese, two French, a Belgian, and a second Briton, according to Egyptian officials, although there were conflicting reports on the 19th victim.
The toll surpasses what was believed to be the deadliest accident in the sport’s 200-year history: In 1989, 13 people were killed when their hot air balloon collided with another over the Australian outback.
In 2009, 16 tourists were injured when their balloon struck a cellphone transmission tower over Luxor. A year earlier, seven tourists were injured in a similar crash.