Edmonton 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.
Chief Rod Knecht says officers have one individual in custody and they think he acted alone, but they aren't ruling out that others are involved.
The chaos began outside the Edmonton Eskimos football game at Commonwealth Stadium when police say a vehicle rammed a traffic control barricade and sent an officer flying into the air.
Knecht says the driver of the vehicle then got out and attacked the officer with a knife before fleeing.
The officer was taken to hospital and treated for non life-threatening injuries while a manhunt was launched.
A few hours later, a U-Haul van was stopped at an impaired driving checkstop north of downtown and the driver sped off with police in pursuit.