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All nine National Guard members aboard a decommissioned Puerto Rico National Guard cargo plane were killed Wednesday when it crashed onto a busy roadway near Savannah, Georgia, and burst into flames, officials said.

Authorities said no one on the ground was injured.

Brig. Gen. Isabelo Rivera, the adjutant general, or commander, of the Puerto Rico Guard, said the Guard members were aboard a WC-130 aircraft headed to Tucson, Arizona. Their names are being withheld until their families could be notified, he said.

The plane was attached to the 156th Airlift Wing at Muñiz Air National Guard Base in Carolina, Rivera said.

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The WC-130 Hercules is a high-wing, medium-range aircraft often used for Air Force weather reconnaissance missions. Rivera said the plane that crashed Wednesday had been decommissioned because it was one of the oldest in the Puerto Rico Guard's inventory.

Witnesses told NBC affiliate WSAV that the crash took place shortly after takeoff, which Rivera said was at about 11:30 a.m. ET. Images and videos on social media showed a large plume of smoke rising from a fiery aircraft.

Gena Bilbo, a spokeswoman for the Effingham County Sheriff's Office, said the plane didn't hit any cars on the roadway where it crashed — "which is an absolute miracle."

Power was cut to the area as crews worked to secure the scene, she said. She didn't know how many people were without electricity as a result.

The wreckage stretched to nearby railroad tracks, Bilbo said, forcing trains to stop running.

"The impact is huge," she said. "All we can do is try to mitigate it as best we can and say a prayer for the families involved." She added that it could be weeks before the road was reopened.

Some commercial flights were delayed by the crash, which took place just off Savannah/Hilton Head International Airport, airport officials said.

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