SYRACUSE, N.Y. (AP) — A house collapsed in Syracuse, New York, on Tuesday, injuring at least 11 people, officials said.

Firefighters responded to multiple 911 calls of what sounded like an explosion at a two-story house at around 4 p.m., Syracuse Fire Chief Michael Monds told reporters at the scene.

Firefighters arrived to find many of the victims already in the front yard but had to pull at least one youth out of a car buried in the rubble, he said.

The residents, a mix of children and adults, were taken to Upstate University Hospital, and two of them were in very serious condition, Monds said. Fire officials said all 13 residents had been accounted for as of Tuesday evening, The Post-Standard reported.

Monds said police and fire officials will be investigating what caused the collapse of the home, which dates to 1920. He noted that responding firefighters also encountered downed power lines and a heavy odor of natural gas at the scene.

More than 50 firefighters responded to the collapse and had to be rotated in and out due to the extreme heat that bore down on Syracuse and other parts of the country Tuesday, Monds said.