A train carrying members of Congress to a Republican retreat in West Virginia slammed into a garbage truck Wednesday, throwing lawmakers from their seats and leaving at least one person dead, officials said.

Authorities identified the person killed as Christopher Foley, 28, of Louisa County, Va., one of two passengers inside the truck. The other passenger, still unidentified, was airlifted to the University of Virginia Medical Center with critical injuries.

The truck's driver, also still unidentified, was transported to a hospital with serious injuries, according to Madeline Curott, public information officer of the Albemarle County, Va., police department.

Several train passengers and crew members, including at least one lawmaker, were rushed to a local hospital for what were largely described as minor injuries.

"It was a very high-speed collision," U.S. Rep. Jeff Denham, R-Calif., who was on board, told Fox News. "There was no braking that was felt. We hit an immediate impact and went from 70 to zero very quickly."

According to numerous accounts, lawmakers on the scene sprung into action to help the injured, including by carrying one individual across the tracks to an ambulance.

'It was a very high-speed collision.' — Rep. Jeff Denham

There were mixed reports on whether the train actually derailed, but sources said the front engine ended up with wheels off the tracks. Lawmakers on the train quickly flooded social media with images of the wrecked truck, as well as damage to the crumpled front of the train.

"There is one confirmed fatality and one serious injury. There are no serious injuries among members of Congress or their staff," White House press secretary Sarah Sanders said in a statement. "Senior Administration officials are in regular contact with Amtrak and state and local authorities. Our thoughts and prayers are with everyone that has been affected by this incident."

After initially claiming there were no reported injuries to passengers or crew members, Amtrak later said two crew members and two passengers "were transported to a local hospital with minor injuries."

"Local law enforcement is investigating the incident," Amtrak said in a statement.

One of those passengers was apparently U.S. Rep. Jason Lewis, R-Minn., who told Fox News he had a “little bit of a whiplash” and “maybe a tiny bit of a concussion.” An aide to House Speaker Paul Ryan, R-Wis., also was taken to the hospital after suffering a head injury, his office said.

Ryan was on the train but is fine, Fox News was told. Senate Majority Leader Mitch McConnell, R-Ky., was not on the train.

The crash unfolded in Crozet, Va., near Charlottesville. Members were on a special chartered Amtrak train to the Greenbrier resort, where Vice President Pence was set to speak Wednesday night, with a planned appearance from President Donald Trump on Thursday. Trump confirmed that he still will be traveling to the retreat, adding that the crash was “a pretty rough hit, that’s what they all tell me.”

The retreat is where the party traditionally gathers to discuss its agenda and goals for the coming year -- and was starting a day after Trump's State of the Union address.

The retreat is expected to go on as planned. The train -- which had a functional engine on the other end -- was able to run in reverse back to Charlottesville, where members were taking buses to West Virginia.

While injuries on the train were largely described as minor, U.S. Rep. Roger Marshall, R-Kan., a medical doctor, tweeted that he was helping the injured immediately after the crash.

"We are on our way to our annual GOP retreat, the train carrying members and spouses hit something. Laina and I are ok, I am helping those that are injured, I will have Laina keep you updated as I know more," he tweeted.

A Politico reporter, U.S. Rep. Greg Walden, R-Ore., and others posted photos of the wreckage of the truck, where the most serious injuries were reported.

In a phone interview from the train, U.S. Rep. Mark Walker of North Carolina described several helicopters in the air, saying there was also “lots of armed security” working to determine it was an accident and “there was no nefarious behavior.”

“We don't think that's the case,” he told Fox News.

The crash is the latest tragedy to affect congressional Republicans, who were targeted in a shooting last summer at a baseball practice in northern Virginia. The lawmaker most seriously injured in that attack, U.S. Rep. Steve Scalise, R-La., was not on the train Wednesday.

The crash also follows another fatal incident last January when a motorcade was shuttling Senate Democrats to their retreat in West Virginia. When an SUV stopped for the motorcade, the vehicle was rear-ended and exploded; the driver died.

Fox News' Mike Emanuel, Alex Pappas and Jon Decker contributed to this report.