Honolulu firefighters are still trying to determine the cause of a two-alarm fire that caused $20,000 worth of damage to the roof top of one of the towers at the uncompleted Disney hotel at Ko Olina yesterday evening.

Capt. Gary Lum, Honolulu Fire Department spokesman, said the fire was reported at 6:13 last night and caused $10,000 worth of damage to the structure and another $10,000 to the contents of the building.

Hotel spokesman Todd Apo said construction workers were fighting the small fire with fire extinguishers on the 12th floor roof of the eastern tower.

The fire was reported extinguished at 6:39 p.m.