Here is Waukesha police chief Dan Thompon’s full statement at a press conference just now.

“The Waukesha Christmas parade was taking place when a red SUV drove through the barricades, westbound, heading down down Main Street.

“The vehicle struck more than 20 individuals. Some of the individuals were children, and there were some fatalities as a result of this incident.

“We will not be releasing information on fatalities at this time while we are waiting notifying the family members of the deceased.

“An officer did discharge his weapon at the suspect vehicle to try to stop the vehicle. No bystanders were injured as a result of the weapon discharge. The officer involved has been with the department for six and a half years.

“Victims were transformed by the fire department to the hospital; Chief Howard will speak on that. Police Officers also transferred victims to the hospital, and family members also transferred victims from the scene to the hospital.

“We’re no longer looking for a suspect vehicle; we do have a person of interest in custody at the moment. But this is still a very fluid investigation.

“I was present at this tragic event and saw first hand the resiliency of the community coming together.”

Police chief Dan Thompson said he doesn’t know yet if there was any connection to terrorism here.

He said that police do not believe the driver fired a gun from the vehicle, as some early reports had indicated.

Instead, he said, one police officer shot at the SUV in an attempt to stop it. The shots didn’t injure any bystanders.

Waukesha police are being assisted by the FBI, the ATF (Bureau of Alcohol, Tobacco, Firearms and Explosives), and neighbouring police departments, Chief Thompson added.

There were 12 children injured in the attack, Chief Thompson says.

He said that 11 adults and 12 paediatric patients were transported to local hospitals. The vehicle struck more than 20 people.

It is not clear whether those numbers include the dead. Another official said there were “some fatalities”, suggesting more than one.

Police chief Dan Thompson has said a person of interest is in custody.

He confirmed that more than one person is dead, but refused to say how many because police are still working to contact family members.

The press conference has started. Mayor Shawn Reilly said:

“Today we experienced a horrible, senseless tragedy. I walked in the parade. At the beginning I saw the happy children sitting on the curb…

“Today our community faced horror and tragedy in what should have been a community celebration. I’m deeply saddened to know that so many in our community went to a parade but ended up dealing with injury and heartache.”

A Waukesha school district board member named Cory Montiho has spoken to the Milwaukee Journal Sentinel, saying the car hit his daughter’s dance team.

Mr Montiho said: “They were pom-poms and shoes and spilled hot chocolate everywhere. I had to go from one crumpled body to the other to find my daughter. My wife and two daughters were almost hit. Please pray for everybody. Please pray.”

Angelito Tenorio, an alderman in West Allis, told the Wisconsin State Journal: “We heard a loud bang, and after that we just heard deafening cries and screams from the crowd, from the people at the parade. And people started rushing, running away with tears in their eyes crying.”

Another video taken from within the crowd by the side of the parade shows the red SUV flashing through the assembled marchers and running some of them over.

In the aftermath, people can be heard screaming and some can be seen lying on the ground needing medical attention. Lawn chairs and other objects are strewn around, and the music for the parade continues to play over loudspeakers.

Waukesha City Council member Cory Payne said: “There [were] many people — or at least a few people — that were completely nonresponsive. And then several others that were desperately in need of medical attention.”

A horrific video obtained by Milwaukee TV station TMJ 4 shows the red SUV ploughing at high speed into the parade from behind.

With band members marching four abreast in close formation, the car hits multiple people in a line, at one point bucking as it appears to run someone over.

It slows down as it pushes through the parade and then breaks through the other side, driving away until it is not visible.

We’re just awaiting a press conference from police now.

Wakesha police have sent out an emergency alert on smartphones warning anyone within half a mile of the incident site to shelter in place and wait for an all clear.