INDIANAPOLIS (AP) _ The body of a 5-year-old girl was found Monday in the wreckage of an Army base apartment building leveled in an explosion apparently caused by a natural gas leak.

Seventeen people were injured, four critically, in the Sunday night blast. Fort Benjamin Harrison residents criticized the Army for failing to adequately warn them of the danger of the gas leak.

The explosion ripped through a four-unit apartment building in Harrison Village, destroying it and heavily damaging a second building, base officials said.

The blast occurred hours after fire authorities arrived to investigate a gas leak at another building in the complex, which housed enlisted personnel. That building was being evacuated when the blast went off several hundred feet away, said Major Ronald Downing.

Marion County Deputy Coroner Charles W. Green said he could not conclusively identify the dead child discovered by rescue workers Monday morning until after dental records were checked. However, base officials said there was little doubt it was a 5-year-old girl who had been reported missing earlier. The girl's identity was not released.

As fire officials investigated the leak, military police notified some residents that their gas was turned off and they might not have heat until Monday, said Sgt. Clayton R. Glass, who first reported the leak behind his quarters.

''We all knew what it was as soon as we heard it. ... We all smelled gas outside, it was so thick,'' said Victoria Glynn, a resident.

She said military police asked residents if they wanted to be evacuated to a hotel or to stay in their homes. ''We thought it was for our convenience because we wouldn't have heat. We were never told there was possible danger.''

Joan Adams, another resident, said military police who knocked on her door told her ''there was no danger for us to stay here.''

Lt. Col. Bill Carey, provost marshal, said, ''We didn't feel the whole area needed to be evacuated.''

''We don't know exactly what caused the explosion,'' said Dan O'Brien of Citizens Gas Co., which supplies gas to the base-operated system.

''What puzzled us was the fire continued,'' he said.''It was gas-fed, which surprised us because the gas was shut off.''

Residents of the 240-unit complex were allowed to return briefly Monday to gather belongings, but they were not told when they could move back.

Six people remained hospitalized for treatment of severe burns, four in critical condition and two in serious condition, authorities at Riley and Wishard Memorial hospitals said Monday. Eleven rescue workers and military personnel were treated and released.