A number of people have been injured after a vehicle drove through a holiday parade in the US state of Wisconsin, according to reports.

The incident happened in Waukesha, which is about 20 miles west of central Milwaukee, just before 5pm on Sunday.

In footage on social media, the red vehicle appeared to speed towards marchers from behind, with police opening fire on it as it crashed through street barriers.

Waukesha Mayor Shawn Reilly confirmed many people had been injured but said he did not believe there was any current danger to the public.

Angelito Tenorio, who was at the parade, told the Milwaukee Journal Sentinel: "As we were walking back in between the buildings... we saw an SUV cross over, just put the pedal to the metal and just zooming full speed along the parade route.

"And then we heard a loud bang, and just deafening cries and screams from people who are struck by the vehicle."