At least two people are dead after a helicopter crashed in a residential neighborhood in Pennsylvania, a spokesperson for Cumberland County told CBS News. The spokesperson said both victims were in the helicopter and no one on the ground was hurt.

The victims' names haven't been released. The spokesperson confirmed that the chopper wasn't being used for medical transport but didn't indicate what the nature of the flight was..

It's unclear what caused the crash Thursday night in Silver Spring Township. Residents told CBS Harrisburg affiliate WHP they heard the chopper above their homes. Emergency crews remain at the scene.

We're following a deadly helicopter crash in Silver Spring Township, Cumberland County. Coroner is on scene. @BrendanRKinney pic.twitter.com/K3myuW6XF9 — CBS 21 News (@CBS21NEWS) January 10, 2020

The Federal Aviation Administration confirmed that a Robinson R66 helicopter carrying two people crashed into a "residential backyard" near Harrisburg at about 9:15 p.m. The agency said it will investigate the incident. National Transportation Safety Board (NTSB) will, as well.

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The county spokesperson said the investigation would likely be a "long, drawn-out process."