Canadian police say an attack on an officer outside a football game and a high-speed chase of a U-Haul that left four people injured are being investigated as acts of terrorism.

Edmonton Police Chief Rod Knecht said early Sunday officers have one person in custody and they think he acted alone.

The chaos began outside a Canadian Football League game when police say a vehicle rammed a traffic control barricade and sent an officer flying.

Knecht said the driver then got out and attacked the officer with a knife.

A few hours later, a U-Haul van was stopped at an impaired driving check stop and the driver sped off with police in pursuit.

Police say the U-Haul hit and injured four pedestrians before it rolled and the suspect was arrested.