The balloon which was carrying 21 people was flying at 300 metres (1,000 feet) caught fire when it caught fire, a security official said.
An employee at the company operating the balloon said the pilot and one tourist survived by jumping out of the basket before it plunged to the ground. Both have been taken to hospital.
The employee, who declined to give her name, told AFP the tourists were from Korea, Japan and Britain, as well as one Egyptian.
Earlier a security official reported 19 people dead but said they were from Hong Kong, Japan, France and Britain.
"This is terrible, just terrible," the employee told AFP by telephone. "We don't yet know what happened exactly or what went wrong," she said.