The balloon is believed to have caught fire and exploded, before plunging into a sugar cane field west of Luxor, which is 320 miles (510km) south of the capital Cairo.
The casualties are believed to include British and French tourists, as well as other nationalities, said a security official in the country.
A Foreign Office spokesman: "We are aware of the reports and we are making urgent inquiries with the authorities in Egypt."
An AP reporter at the crash site said he saw eight bodies being put into body bags and taken away.
According to one report one tourist and the balloon pilot survived the accident, which happened after a gas explosion at an altitude of 1,000ft.