NEW CASTLE, Del. -- A medical helicopter has crashed behind a postal facility in a Delaware industrial park, killing the pilot, authorities said. No other injuries have been reported.

The Federal Aviation Administration said in a statement that the Eurocopter E135 helicopter crashed just before noon Thursday about 1 mile southeast of New Castle Airport. It wasn't immediately clear what caused the crash.

Police said the chopper burst into flames upon crashing, CBS Philly reported.

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Delaware State Police spokesman Cpl. Jeffrey Hale said the pilot -- a 37-year-old man from Franklinville, New Jersey -- was the only person on board and was pronounced dead at the scene.

Hale said the helicopter crashed into a ditch behind a U.S. Post office facility, causing minor damage to an outbuilding and vehicles parked behind the building. Hale said that Hazmat responded to the scene and that nobody on the ground was injured.

"With any crash of this magnitude, obviously there is fuel on board and there's a possibility of a spill," he added.

The NTSB was en route and expected to arrive later on Thursday.

One Twitter user posted an image that he said was taken by his friend. CBS News confirms that it shows the aftermath of the crash.

A helicopter just crashed in Delaware... pic.twitter.com/JnSwjDWIKY — Yilu @ U.S. (@zhouyilu) May 25, 2017

Ryan Dillman, a worker at a nearby business, told The News Journal of Wilmington that he heard a noise outside that "kept getting stronger and stronger."

"Right when we looked out, it crashed and exploded. There were flames everywhere, and smoke. My heart dropped," he said.

"I heard this blurb blurb blurb and then I looked up in the sky," Marian Williams, who saw the helicopter nosedive, told CBS Philly. "I heard it explode and then I saw this gulf of black smoke. It was terrifying. It still is. I'm still shaking."

"I'm still shaken about it and I'm sad ... there was a life there and it's gone," Williams said.

Susan Phillips, Penn Medicine's SVP for Public Affairs, said in a statement to CBS News that the incident involved a helicopter operated by Metro Aviation, which provides aviation services for PennSTAR, the air transportation service for the University of Pennsylvania Health System.

"The pilot of the helicopter was conducting a training flight. No patients or Penn Medicine employees were on board. We have no further information at this time," she wrote.

Kristen King Holmes, marketing director for Metro Aviation, based in Shreveport, Louisiana, said in an email that the company has sent operations, safety and maintenance personnel to the scene.

"Our thoughts and prayers are with our pilot's family and the entire Metro Aviation and PennSTAR family," Holmes wrote.

James Salmon is a spokesman for the airport's operator, Delaware River and Bay Authority. He said the helicopter wasn't engaged in life-saving operations.