A Puerto Rican Air National Guard military aircraft with nine people on board crashed and burst into flames shortly after takeoff from a Georgia airport Wednesday, and officials said there appeared to be no survivors.

The WC-130 plane was being flown into retirement when it crashed on a highway just before 11:30 a.m., shortly after takeoff from Savannah/Hilton Head International Airport.

“There has been a plane crash at the intersection of Hwy 21 at Crossgate Rd. Roads will be shut down. Please avoid the area,” Chatham EMA tweeted shortly after the incident.

Photos from the ground showed a section of the plane engulfed by fire and thick black smoke billowing to the sky. Only the tail section of the aircraft was intact.

Mark Jones told Savannah Morning News he was near the highway when he noticed a plane flying dangerously low.

“I could see [the plane] above the tree line and it looked kind of low like it was curving in toward street, but I see them all the time, so I didn’t think anything of it,” Jones said. “I looked down and then looked back up and it didn’t look like it nosedived, but it almost looked like it stalled and just went almost flat right there in the middle of the highway.”

Jones said he saw an explosion and believed the plane could have landed on cars driving on the road.

“There were definitely cars going both ways," he said "...Most people stopped and got out of their cars.”

But Gina Bilbo, spokesperson for the Effingham County Sheriff's Office, said at a news conference Wednesday afternoon that despite Highway 21 being "a very busy roadway," the plane "miraculously did not hit any cars, any homes."

It’s unclear exactly what caused the crash. The Savannah Air National Guard said a board of officers will investigate the incident.

The plane was more than 60 years old, Isabelo Rivera, Adjutant General of Puerto Rico's National Guard, said.

Belonging to the 156th Air Wing, it was used to rescue U.S. citizens stranded in the British Virgin Islands following Hurricane Irma and ferry supplies to Puerto Rico after Hurricane Maria last year.

All nine crew members aboard the plane Wednesday had helped with hurricane recovery efforts, Rivera said.

President Trump tweeted that he had been briefed on the crash and asked for "thoughts and prayers for the victims, their families and the great men and women of the National Guard."

Puerto Rico Gov. Ricardo Rossello tweeted that his thoughts are with those impacted by the crash, and that they'll receive support from the Puerto Rico National Guard.

Savannah/Hilton Head International Airport said flights were being impacted by the plane crash and urged travelers to check with airlines regarding their travel. Meanwhile, Highway 21 will remain closed "indefinitely," according to officials.

A WC-130 is a weather reconnaissance aircraft used by the Air Force and Air National Guard. Typically an Air Force plane like this has a crew of five, with room for dozens of passengers or cargo.

In the past month, eight U.S. military non-combat aviation crashes have killed at least 12 service members. Top Marine Corps and Navy officers at the Pentagon on Wednesday said budget cuts over the past decade were partially to blame for the spate of training crashes.

Fox News' Shira Bush, Lucas Tomlinson and The Associated Press contributed to this report.