An early morning fire yesterday at a Southeast Washington apartment house sent thick black smoke through the three-story brick building and forced almost a dozen residents to jump from windows to safety, the D.C. Fire Department reported.

Fire officials said 13 persons, ranging in age from 18 months to 40 years, were injured in the 1:30 a.m. blaze at 406 Condon Ter. SE. Two persons were admitted to local hospitals and were listed in good condition yesterday. The others were treated for smoke inhalation or minor cuts and bruises suffered when they jumped from the building, the hospitals reported.

Firefighters said that when they arrived, black smoke was gushing from windows and residents were yelling for help, many screaming that they had small children inside who needed to be saved.

"When we pulled up, we saw flames in the back and people bailing out the windows in the front," said firefighter Rick Knight of Engine Co. 25, the first on the scene.

"Everybody was a little hysterical. We were trying to get them to stay in the building until we could get ladders to them, but there was a lot of thick, black smoke and they couldn't see or breathe," he said. "Any normal person would panic in a situation like that."

Knight said that most of the persons were jumping from second- and third-floor windows, but that firefighters were able to calm many of the residents and rescued at least eight by ladder. He said that one man threw a mattress from his window and then jumped onto it.

It took firefighters about 20 minutes to extinguish the blaze that started in an apartment on the second floor and extended into a hallway, fire officials said. They said the cause of the fire, which apparently was accidental, is under investigation.