11.   Arson was suspected of causing the blaze, according to Israel radio.

12.   Authorities believe an accidental explosion caused the blaze.

13.   Authorities said officials were not ruling out the use of an accelerant but were not ready to say what caused the blaze.

14.   Austrian radio said the blaze was apparently caused by a burning cigarette tossed onto the plastic foam, which the disco management had been told was fireproof.

15.   Authorities said they were not ruling out the use of an accelerant but were not ready to say what caused the blaze.

16.   Civil defense officials told the state-run agency the blaze was caused by an electrical short circuit.

17.   Criminal police joined the investigation to determine whether the blaze was caused by arson.

18.   Faulty wiring in two old air conditioners was believed to have caused the blaze.

19.   Fire marshals were at the scene trying to determine what caused the blaze.

20.   Fire information officer Christa Orozco said the blaze was caused by humans, but the exact cause was not known.