The Canadian authorities have said that two incidents in Edmonton are being investigated as acts of terrorism after a man struck a police officer with a car before stabbing him and later plowed a truck into pedestrians on a busy street, injuring at least four people.
The authorities said the suspect is "a male Somali national and refugee who was previously known to the Edmonton Police and the Royal Canadian Mounted Police (RCMP)," in a Sunday afternoon press conference.
Formal charges have not been filed against the suspect, who the police believe acted alone.
The first incident happened on 30 September when the driver of a white Chevrolet Malibu drove it into a traffic barricade. The police had set up the roadblock near Commonwealth Stadium for an Edmonton Eskimos football game.
"The police have arrested the suspect for several offenses, including participation in a terrorist act and the commission of an offense for a terrorist group," the CNN quoted Chief Rod Knecht of the Edmonton Police Service, as saying.
"The vehicle struck the police officer, sending him flying into the air 15 feet, before colliding with the police officer's cruiser again at a high rate of speed," Knecht said.
"The driver jumped out of the vehicle, attacked and stabbed the officer several times with a knife and fled on foot. There was an ISIS flag in the car, which has been seized as evidence," he added.
Knecht further said that the wounded officer, Mike Chernyk, had severe abrasions on his arms and suffered stab wounds to his face and head, but will make a full recovery.
"During the chase, the truck deliberately attempted to hit pedestrians in crosswalks and alleys in two areas along Jasper Avenue," Knecht said.
At least four pedestrians were injured.
Two of the victims were later released from the hospital. The others were kept for further observation.
The suspect was investigated in 2015 after police received a complaint he was "espousing extremist ideology," said RCMP Deputy Criminal Operations Officer Marlin Degrand, but there was insufficient evidence to pursue terrorism charges.
The suspect was not deemed to be a threat at the time, Degrand said.
"The Government of Canada and Canadians stand with the people of Edmonton after the terrorist attack on 30 September that sent an Edmonton Police Service officer to (the) hospital and injured a number of innocent people who were out to cheer on their football team and to enjoy an evening in their city," said Canadian Prime Minister Justin Trudeau in a statement on Sunday.
"We cannot -- and will not -- let violent extremism take root in our communities. We know that Canada's strength comes from our diversity, and we will not be cowed by those who seek to divide us or promote fear," he added.