media captionLondon, Ontario police: "We believe the victims were targeted because of their Islamic faith"
Canadian Prime Minister Justin Trudeau has identified the four members of a Muslim family killed in a "premeditated" attack on Sunday.
Madiha Salman, 44, her husband Salman Afzaal, 46, their 15-year-old daughter Yumna Afzaal and Mr Afzaal's 74-year-old mother were hit by a vehicle while on an evening walk in London, Ontario.
Mr Trudeau condemned the attack as an act of terror.
The couple's nine-year-old son survived and is in hospital with injuries.
The attack was the worst against Canadian Muslims since six people were killed in a Quebec City mosque in 2017.
A 20-year-old Canadian man has been charged with four counts of murder and one count of attempted murder.
Police said the family is believed to have been targeted because of their Muslim faith. Authorities are weighing possible terrorism charges for what is thought to be a hate crime.
Speaking in the Canadian House of Commons on Tuesday, Mr Trudeau decried "a terrorist attack motivated by hatred, in the heart of one of our communities".
"If anyone thinks racism and hatred don't exist in this country, I want to say this: how do we explain such violence to a child in a hospital? How can we look families in the eye and say, 'Islamophobia isn't real'?" he said.
A vigil has been planned for Thursday evening at the London mosque the family attended.
Who are the victims?
Three generations of the Afzaal family were killed on Sunday while out for an evening walk. Five family members were waiting to cross an intersection along London's Hyde Park Road when the truck mounted the curb and hit them, police said.
Family and friends told CBC News that the family had been deeply involved in their community and committed to their faith.
After graduating from the London Islamic School last year, 15-year-old Yumna was in the ninth grade at Oakridge Secondary School.
At Oakridge, Yumna was slated to become a Grade 10 representative on the Muslim Students Association, the organisation's president told CBC.
Yumna's mother, Ms Salman, had recently completed a post-graduate degree in civil and environmental engineering at Western University in London, according to her LinkedIn page. Her goal was to work on solving "geo-environmental issues" and "contribute towards reclamation of our natural environment".
Salman Afzaal was "humble" and loyal to his community, a friend told CBC.
The name of Mr Afzaal's 74-year-old mother has not yet been released.
The couple's nine-year-old son was the only family member present who is expected to survive. He remains seriously injured in hospital.
What's behind the attack?
Police named the alleged attacker as Nathanial Veltman, 20, of London, Ontario. He was arrested without incident at a shopping centre about 6km (4.8 miles) from the crime scene.
It is not yet known if the suspect has ties to any hate groups, said Det Supt Waight.
image copyrightReutersimage captionA makeshift memorial for the victims was set up at the scene of the attackimage copyrightReutersimage captionMany local residents were in shock after the attack
"There is no known previous connection between the suspect and the victims," Det Supt Waight said, adding that the suspect was wearing a vest that appeared to be "like body armour".
Police said Mr Veltman had no previous convictions.
Officials added that there was good weather and high visibility conditions when the black truck was seen mounting the kerb on Hyde Park Road at around 20:40 local time on Sunday.
One witness told CTV News she had to shield her young daughter's eyes from the bodies.
"There were people everywhere and running," said Paige Martin. "Citizens were trying to direct the emergency vehicles where to go. There was a lot of pointing and screaming and arm waving."
A 2016 census found that London – a city about 200km (125 miles) south-west of Toronto – is growing increasingly diverse. One in five people was born outside of Canada, with Arabs being the area's largest minority group, and South Asians coming in a close second.
'Brutal, cowardly act of violence'
Mr Trudeau addressed parliament in the wake of the attack, describing a "brutal, cowardly, and brazen act of violence".
The perpetrator "does not represent us as Canadians", the prime minister said, but he dismissed the notion that this type of violence is not "Canadian" – a sentiment echoed by Canada's opposition leaders.
"We need to look this in the face – this hate does exist in our country," Mr Trudeau said.
London Mayor Ed Holder was among those who paid tribute to the victims, saying: "This was an act of mass murder, perpetrated against Muslims, against Londoners, and rooted in unspeakable hatred.
Mayor Holder said he was speaking "on behalf of all Londoners when I say our hearts are broken".
"We grieve for the family, three generations of whom are now deceased."
The mayor's statement added that he had ordered flags outside London City Hall to be lowered for three days of mourning.
image copyrightReutersimage captionPolice believe the victims were targeted because of their faith
It is not the first time members of the Muslim community in Canada have come under attack.
In January 2017, a Canadian man fatally shot six worshippers at the Quebec Islamic Cultural Centre, and seriously injured five others. The perpetrator was sentenced to life in prison.
Canada's deadliest vehicle-ramming attack happened in 2018, when a self-described "incel" (involuntary celibate) ploughed his van into a group of pedestrians in Toronto, killing 10 people.