Four members of a Muslim family have been killed in a "deliberate" planned attack, Canadian police have said.
A young boy was also injured and has been hospitalised after a pickup truck was driven into the family in the Ontario city of London.
Police said the driver of the truck mounted the pavement and struck the family at a junction on Sunday, killing four.
A 20-year-old man was arrested at a nearby car park after the incident and faces four counts of first-degree murder and one count of attempted murder.
Police say that the man, also a resident of London, did not know the victims but had targeted them because they were Muslims.
The incident is the deadliest anti-Muslim attack in Canada since six people were killed by a far-right supremacist in a shooting at a Quebec City mosque in 2017.
"This was an act of mass murder perpetuated against Muslims,” said London Mayor Ed Holder, "it was rooted in unspeakable hatred." The mayor added that flags would be lowered for three days in the city of London.
"To the Muslim community in London and to Muslims across the country, know that we stand with you," tweeted Canadian Prime Minister Justin Trudeau.
"Islamophobia has no place in any of our communities. This hate is insidious and despicable — and it must stop."
The names of the victims have not been released, but they are a 74-year-old woman, a 46-year-old man, a 44-year-old woman and a 15-year-old girl, representing three generations of the same family, Mayor Holder said.
In a statement, the extended family of the victims described them as a "model family" of Muslims, Canadians and Pakistanis.
"They worked extremely hard in their fields and excelled. Their children were top students in their school and connected strongly with their spiritual identity."
The family added in its statement that the public needs to stand against hate and Islamophobia.
"This young man who committed this act of terror was influenced by a group that he associated with, and the rest of the community must take a strong stand against this, from the highest levels in our government to every member of the community," they said.
Police said they had not determined if the suspect was a member of any specific hate group, and were working with prosecutors on potential charges of terrorism.
"We believe the victims were targeted because of their Islamic faith,” said police chief Stephen Williams. "There is no tolerance in this community who are motivated by hate and target others with violence."
The head of the National Council of Canadian Muslims has described the killings as a "terrorist attack".
Bouquets of flowers were laid at the scene of the attack throughout Monday evening, and a vigil for the victims is planned at a mosque in London on Tuesday.