1 person rescued overnight as crews race to find anyone who may be trapped after an apartment building's partial collapse in Davenport, Iowa

An eighth person has been rescued after a six-story apartment building partially collapsed Sunday in Davenport, Iowa, as crews scramble to find anyone else who might be trapped.

While "no known individuals are trapped in that facility," rescue teams with search dogs are still scouring the wreckage Monday morning, Davenport Chief Mike Carlsten said. He said no fatalities have been reported.

Still, "the building is structurally unsound, is posing a risk to responders," Carlsten said. He said structural engineers are on site as first responders prepare to shift from rescue operations to recovery.

It's not clear how many people may be unaccounted for or how many residents are displaced.

Crews were dispatched around 4:55 p.m. Sunday to the apartment building known as The Davenport, Carlsten said. Part of the building's back section collapsed and detached from the rest of the structure, the fire chief said.

"I live in the building just next to it, and we heard just like a large crash," Andrew Sommer, a former tenant of The Davenport, told CNN affiliate KWQC. "Shortly after, we went outside and saw the whole section of the building gone."

The collapse led to "a large natural gas leak" and quite a bit of water gushing in the building, the fire chief said. Crews managed to stop the leaks and resume their search for survivors.