Oct. 1 (UPI) -- Canadian authorities announced an investigation into a pair of possible terrorist attacks on Sunday morning.
A man struck an Edmonton police officer with a car and stabbed him, and four pedestrians later were hit by a truck driving on a street.
"We are urging Edmontonians to be vigilant and aware of their surroundings," Edmonton Police Service Chief Rod Knecht said in a 3 a.m. news conference.
A police officer was controlling traffic at a Canadian Football League game around 8:15 p.m. on Saturday when he was hit by a white Chevrolet Malibu going at high speed through the traffic barricades and then attacked with a knife by the driver. The officer was hospitalized but his injuries are not thought to be life-threatening.
Around midnight, police pulled over a U-Haul rental van. The officer noticed the driver's name was "very similar" to that of the Malibu's registered owner.
The driver took off and was pursued by police toward downtown Edmonton, and "throughout the chase, the truck deliberately tried to hit pedestrians in crosswalks." Four people were hospitalized with unspecified injuries.
The van driver was arrested after a police chase.
"The driver was apprehended and taken into police custody," Knecht said. "It is believed at this time that these two incidents are related."
Police believe the suspect acted alone, but haven't rule out involvement by others.