Authorities are investigating an early Wednesday morning fire at a Silver Spring building that houses a school and a Masonic lodge.

Fire officials are combing a two-story building on University Avenue for clues that could help them understand what started the 4:30 a.m. blaze. The 100 foot by 200 foot, two-story commercial building is home to a Masonic lodge and the National Children’s Center, a school for people with developmental disabilities.

Pete Piringer, spokesman for the Montgomery County Fire and Rescue Service, said authorities did not find any immediate cause for suspicion, but arson has not been ruled out as a cause of the fire. The fire was on the second floor of the building, he said.

Fire fighters got the blaze under control within 20 minutes, Piringer said.

A fire alarm alerted authorities, he said.

Officials on Wednesday morning closed parts of University Boulevard and Dennis Avenue because of the fire. Authorities later opened most of the lanes to traffic.