41.   Korver said it was not known what caused the rise.

42.   She said it was not yet known what caused the riot.

43.   She said it was not immediately known what caused the smoke.

44.   That indicated that he was still close to Saddam then, and it is not known what caused him to flee.

45.   Gonsalves said it was not known what caused the rockfall.

46.   Gonsalves said it was still not known what caused the rockfall.

47.   It was not immediately known what caused part of the three-storey tourist apartment block on Burras beach near San Bartolome de Tirajana to crumble.

48.   It was not known what caused the accident.

49.   It is not known what caused the leak.

50.   It is not yet known what caused the explosion which occurred early Sunday.