DALLAS (AP) — A freight train slammed into a parade float carrying wounded veterans on Thursday, killing four people and injuring 17 others as the float tried to get through a West Texas railroad crossing on its way to an honorary banquet, authorities said.

The locomotive was sounding its horn and people were jumping off the decorated flatbed truck before the collision around 4:40 p.m. in Midland, according to witnesses and Union Pacific spokesman Tom Lange. A preliminary investigation indicates the crossing gate and lights were working, Lange said, though he didn't know if the train crew saw the float approaching.

Two people died at the scene, while two others died at Midland Memorial Hospital, City of Midland spokesman Ryan Stout said. Seven of those injured are in critical condition, while the 10 others are in stable condition, he said.

About two dozen veterans and their spouses had been sitting in chairs on the float, set up on the back of a flatbed tractor-trailer decorated with American flags and signs identifying each veteran, photos show.

Panic swept through those seated on trailer as the locomotive's horn sounded, said Patricia Howle, who was waiting at a nearby traffic light as the train approached.

"My daughter said, 'Momma, the train is coming!' and she was looking for it as I saw the trailer begin to cross the railroad tracks," Howle told KOSA-TV. "People were jumping off, trying to get off that trailer and the truck was still rolling.

"People on the trailer saw the train coming and they were flying in every direction," she added. "I covered my face. I didn't want to see."

The float was among two flat-bed trucks carrying veterans and their spouses, police said. The first truck safely crossed the railroad tracks, but the second truck's trailer was hit by the train. Police said some of the people on the second trailer were able to evacuate before the crash.

A banner across the truck's front bumper read, "Heroes on Board."

The parade was to end at a "Hunt for Heroes" banquet honoring the veterans. The wounded service members were then going to be treated to a deer-hunting trip this weekend. The events have been canceled.

Lange said Union Pacific is offering help to the community and victims' families, as well as peer-to-peer counseling for the train crew, who did not sustain any injuries.

"There is going to be a very thorough investigation," Lange said. "It's obviously a very tragic incident."

The National Transportation Safety Board also is investigating, NTSB spokesman Peter Knudson said.

Midland is about 320 miles west of Dallas.