The Champlain Towers South building in Surfside, Florida unexpectedly collapsed on Thursday morning.
  • Florida firefighters heard a banging noise during rescue operations at a collapsed condo building.
  • At least one person died when a section of Champlain Towers South collapsed Thursday morning.
  • An investigation is underway.
  • For more stories visit Business Insider.

Firefighters who are tunnelling under the condo building that collapsed Thursday morning in Miami are hearing noises that could be coming from survivors.

At a press conference Thursday evening, Miami-Dade Fire Rescue Assistant Chief Ray Jadallah said sonar devices were picking up noises from within the rubble.

"We did receive sounds," Jadallah told reporters. "What sounds like people banging - well not people, but sounds of a possibility of a banging. Short of that, we haven't heard any voices coming from the pile."

Jadallah said 37 people have now been pulled from the site, including 35 from the structure itself and two from the rubble.

This is a developing story. Check back for updates.

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