A three-alarm fire of suspicious origin swept through the officers' club at Bolling Air Force Base in Southeast Washington yesterday, injuring seven firefighters, none seriously, fire officials reported.

It was the second suspicious fire at the club in a month, the officials said.

Yesterday's blaze, discovered about 10:15 a.m., caused "extensive damage" to the club, a large, two-story white brick and cement building on Westover Avenue SE, near the Portland Street exit of South Capitol Street.

"It was ugly," said a firefighter from the Naval District of Washington Fire Department, which was assisted in fighting the blaze by the D.C. Fire Department. "When we got here, fire was blowing out past the trees," about 25 feet from the main entrance.

Naval fire officials and the FBI are investigating the cause of the blaze, which started in the basement area of the building near the Brass Works Lounge, according to Sgt. Alfreda Carter, a spokeswoman for the base. She said the fire was officially listed as suspicious in origin.

The building also houses ballrooms, bars and a restaurant. There was smoke, water and fire damage throughout, Carter said. Federal authorities have not determined the extent of damage yet, but a D.C. fire official said he believed it might be as high as $1 million.

Carter said that there was another "major" fire at the officers' club on May 17, but that details of that blaze were not available. D.C. fire officials said the earlier blaze was also suspicious and was in roughly the same area as yesterday's.

A third fire on March 22, which was caused by a welder's torch, severely damaged the base administration building.

Fire department spokesman Ray Alfred said it took 95 firefighters about an hour to bring yesterday's fire under control. He said the fire "apparently had a good start and was burning for a while" before firefighters arrived.

Forty persons, most of them employes who were inside the building when the fire was discovered, escaped without injury, Carter said.

Firefighters said the blaze apparently spread quickly along wood paneling in the basement area and broke through the floor to second-floor ballrooms. An open stairwell acted like a "natural flue," and the fire "just zoomed up the steps," according to Alfred.

Firefighters said the fire was especially difficult to combat because the building has few windows, and thick black smoke and intense heat had accumulated inside. Billows of smoke could be seen up to two miles away, officials said.

Acting Operations Chief Philip A. Matthews said firefighters also were hindered by exposed electrical wires in the basement. He said that firefighters on the roof of the building were called down because the roof was buckling and looked as if it might cave in.