A train crashed into a float carrying veterans during a parade in Texas Thursday afternoon, killing four people and injuring 17, with many individuals in critical condition.

The train collided into the float during a parade that was part of the “Hunt for Heroes” event in Midland, Texas, the Associated Press reported. The train crashed into the float around 4:30 p.m. local time.

According to city spokesman Ryan Stout, the train crashed into the float at the Union Pacific railroad crossing, the AP noted. Sonny Cleere, the Hunt for Heroes organizer, said the parade was heading for a banquet for in honor of wounded veterans, Reuters reported.

The crash left four dead and 17 injured. Of the 17 injuries, 10 are critical, while seven people are in stable condition. The 17 individuals are being treated at the Midland Memorial Hospital, according to the AP.

The float was a part of the ninth annual Show of Support parade, the Midland Reporter-Telegram said. The float was carrying 24 veterans and their spouses, and it was carried by two trailers. The first trailer successfully made it across the railroad crossing, but the train crashed into the second trailer. The Hunt for Heroes event is set up to provide wounded veterans with a free hunting trip while their spouses have their own schedule of events, the Reporter-Telegram said.

All of the scheduled events have been canceled, KDFW reported. There are varying reports about what caused the train crash, with some saying that the railroad crossing arms did not come down, while other reports differ.

The National Transportation Safety Board has begun investigating the collision, the AP said.