A hot air balloon exploded and plunged to earth at Egypt's ancient temple city of Luxor during a sunrise flight on Tuesday, killing up to 19 tourists, including Asians and Europeans, sources said.
The balloon carrying 21 tourists from Hong Kong, Japan, France, Britain and Hungary was flying at 300 metres (1,000 feet) when it caught fire and exploded, a security official said.
The pilot and one tourist survived by jumping out of the basket moments before it hit the ground, said an employee at the company operating the balloon, Sky Cruise. Both were taken to hospital.
"This is terrible, just terrible," the employee told AFP by telephone, declining to give her name. "We don't yet know what happened exactly or what went wrong."
Luxor Governor Ezzat Saad imposed an immediate ban on all hot air balloon flights in the province as Prime Minister Hisham Qandil ordered an investigation into the accident.
Security services cordoned off the scene of the crash in Luxor's dense sugar cane fields, as police and residents inspected the charred remains of the balloon.
"There was a terrifying sound when the balloon exploded," one resident, Ahmed, 40, told AFP.
"Bodies engulfed in flames were falling out of the balloon," said Youssef al-Tayyeb, another resident who witnessed the accident.
The balloon had been floating over the west bank of Luxor, one of Egypt's most renowned archaeological sites and home to the famous Valley of the Kings and the grand Temple of Hatshepsut, when it exploded.
There was confusion over the exact death toll and the tourists nationalities, with different official bodies giving conflicting figures and details.
An Egyptian security official said 19 tourists from Hong Kong, Japan, Britain, France and Hungary had died. The health ministry put the toll at 18 dead.
Along with the confirmed deaths of two French tourists and two Britons, nine of those killed were thought to be from from Hong Kong, and four from Japan.
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"I can confirm that sadly two of our citizens died in this accident," said French foreign ministry spokesman Philippe Lalliot. "We are in contact with their families."
British tour operator Thomas Cook said three of its clients had also died in the crash.
"We can confirm the tragic deaths of two British nationals and one British resident following a hot air balloon crash in Luxor, Egypt earlier today," said the British Foreign Office
One British tourist was "in a stable condition" after surviving the plunge.
Another tourist who died was understood to be a Hungarian who resided in Britain.
"We believe that there is a high possibility that nine of our customers have died," said Raymond Ng, general manager of travel agency Kuoni, which organised the Hong Kongers' tour.
The five women and four men were aged between 33 and 62, Ng said, adding their relatives were flying to Cairo accompanied by three Kuoni staff.
The nine were among a group of 15 Hong Kongers who had left for Egypt on February 22. Ng said that, according to local employees, the balloon caught fire about an hour after it had set off, plummeting to the ground two minutes later.
In Japan, tour company JTB said four Japanese tourists involved in the accident were all confirmed dead. The foreign ministry said it was still seeking further information.
French hot air ballon expert Philippe Buron-Pilatre de Rozier said the blast could have been caused by a leak after a spark caused by a lighter or a cigarette.
Another reason could be wear and tear due to poor maintenance or if the pilot is badly positioned, said Buron-Pilatre de Rozier, adding that hot air balloons such as the ones used in Egypt are generally 40 metres (130 feet) high and can carry up to 25 passengers.
In 2009, 13 foreign tourists were injured when their hot air balloon hit a phone mast and crashed at Luxor. Sources at the time said the balloon was overcrowded.
The crash comes amid widespread anger over safety standards in Egypt following several deadly transport and construction accidents.