Two people were seriously injured Saturday when an antique car “lurched forward unexpectedly” at a May Day parade in Kennebunk, Maine, “crushing several people between the car and a trailer being used as a float with numerous children on it,” local fire-rescue officials said.

The pair had “significant injuries to lower extremities,” officials said. According to the Portland Press Herald, the two — both women — “suffered serious fractures.” A third adult was injured but reportedly did not go to a hospital, while “several children had bumps and bruises,” officials said, adding the incident appears to be a “total accident.”

The crash occurred at the start of the parade formation on Water Street.

“Based on what we were told from eyewitnesses at the scene, all of a sudden, the antique automobile’s engine revved up extremely loud, the tires were screeching, and it lurched forward,” Lt. Chris Russell told the Press Herald, adding, “It was something that caught the driver completely by surprise.”

“It was really before the parade had started moving, so everybody was condensed,” Fire Chief Justin Cooper said.

Officials credited community members, including two physician assistants, with helping in the immediate aftermath.