STATESBORO -- The Georgia Southern campus was sent reeling Wednesday after an early-morning accident took the lives of five students and left two others injured.

In a heartfelt message sent out to the university community Wednesday afternoon, President Brooks Keel confirmed the tragic incident on Interstate 16 in Bryan County.

"The loss of any student, especially in a tragic way, is particularly painful," Keel wrote in his message. "Losing five students is almost incomprehensible."

The five victims, all women, all Georgia residents and all in their junior year at Georgia Southern, are: Emily Clark of Powder Springs; Morgan Bass of Leesburg; Abbie Deloach of Savannah; Catherine (McKay) Pittman of Alpharetta; and Caitlyn Baggett of Millen.

St. Joseph's/ Candler Health System said the students were commuting to St. Joseph's Hospital in Savannah for their last day of clinical training of the school year.

GSU students Brittney McDaniel of Reidsville and Megan Richards of Loganville also were injured in the crash and are being treated for their injuries, Keel said.

The accident was a seven-vehicle pileup early Wednesday morning on eastbound I-16 in Bryan County that apparently was caused by an earlier crash involving a tractor-trailer and an RV. The accident occurred near mile marker 140, about a mile west of the Highway 280 exit, Bryan County Sheriff Clyde Smith said.

The tractor-trailer plowed into an SUV, then rolled over a small passenger car that burst into flames, said Sgt. 1st Class Chris Nease of the Georgia State Patrol. The big truck came to a halt after slamming into the back of a tanker.

The crash resulted in the five deaths and two injuries, Keel said.

"Every one of our students contributes in no small measure, to the Eagle Nation," Keel said. "Our hearts go out to the families, friends and classmates of these students."

Smith said it's one of the worst wrecks he has seen in his 21 years as sheriff.

"You almost can't believe it," he said. "You don't want to see it."

The crash occurred at roughly 5:45 a.m. when, according to the Georgia State Patrol, a tractor-trailer ran into traffic that was stopped while emergency crews were working on the first collision, which took place around 2 a.m., Smith said, adding that he got the call about the first wreck at 3 a.m.

In all, three big rigs, two cars and two pickup trucks were involved in the second wreck, and two people were flown by helicopter to Memorial University Medical Center.

Bryan County Emergency Services Director Freddy Howell said BCES crews were dispatched to the second accident at about 5:55 a.m. and found "several vehicles with patients and one that was occupied and fully engulfed (in flames). Two helicopters were dispatched and used to transport two of the patients and the others went by ambulance or (their own vehicle)."

Nease said the driver of the tractor-trailer had not been cited as investigators worked to determine exactly what happened. The driver's name was not immediately released. State troopers said weather didn't seem to be a factor.

"There was no fog or smoke. It was clear as a bell," said Sgt. Chris Rodewolt of the State Patrol. "We did have heavy, heavy traffic."

Keel said the university flag would fly at half-staff today on campus. Statesboro Mayor Jan Moore said the city would do the same.

"We cry with you, and will join Georgia Southern University in lowering the American flag to half-staff to honor the memories of the students who were lost," she said.

The Associated Press contributed to this article.