HONOLULU -- Fire investigators in Honolulu are looking into what caused a blaze at Central Union Church that damaged 50 percent of the preschool building.

Authorities said the fire started just after 4 a.m. on Wednesday.

Witnesses told KITV that they saw flames shooting up as high as 20 feet.

"The smoke was so high it was above Kapiolani Children's Hospital. I looked across and I could not see the Banyan Street Apartments. I said, 'Wow this is a big fire,'" said witness Joe Ho.

The flames crept close to Kapiolani Medical Center for Women and Children. Smoke reached some of the floors through the air conditioning system. Hospital workers relocated several patients.

Authorities said no one was injured in the blaze. It took more than 40 firefighters to battle the fire. Fire officials said they believe the blaze started in the storage room area. The fire damaged about 50 percent of the preschool.

"It's sad because we look out for the kids," Central Union Church administrator Miguel Asuncion said. "We just hope we can find a place to hold classes and get it going."

There was no damage to the church itself.