"There is evidence that this was a planned, premeditated act, motivated by hate".
Police said family members had requested that their names not be released.
"It is believed that these victims were targeted because they were Muslim..."
London police were called to the single-vehicle crash at the intersection of Hyde Park Road and South Carriage Road around 8:40 p.m.
According to the police, three adults and one teenager died, one child survived the attack.
Another woman, one man and two children were transported to hospital.
A man, 20, was later arrested outside Cherryhill Mall, police said.
Police say the 20-year-old suspect - a resident of London - did not know his victims.More news: Democratic congressman accuses Manchin of voting to 'preserve Jim Crow'
"Justice must be served for the horrific act of hatred that took place in London, Ontario yesterday".
Ford issued a statement offering thoughts and prayers to the victims' families and friends. "These heinous acts of violence must stop".
The mayor of London, Ont., says the killing of four Muslim pedestrians Sunday evening was an "act of mass murder".
Just prior to the attack, Alek Minassian posted on Facebook a reference to an online community of "involuntary celibates" whose sexual frustrations led them to embrace a misogynist ideology.
"There's no place for hatred and Islamophobia in Ontario".
The investigation is ongoing and anyone with further information is being asked to contact police. He has been charged with four counts of first-degree murder and one count of attempted murder.
"Words fail on a day as dark as this", said the city's Mayor, Ed Holder. I pray for their loved ones.More news: G7 reaches historic deal to reform global tax system, United Kingdom chancellor says
One adult woman was pronounced dead at the scene.
Waight said police in London, about 200 km southwest of Toronto, were liaising with the Royal Mounted Canadian Police on potentially filing terrorism charges.
Eyewitness Paige Martin told reporters a black truck blasted past her and ran a red light as she was walking, and then she came upon the scene and saw "chaos": "It was just absolutely like something that you never want to see".
Martin said her auto shook from the force of the passing truck.
"Hate can not win, and every person in Canada must feel safe in their identity", she said. A few dozen people stood on the sidewalk and several drivers got out of their cars to help.
"I'm still in shock", said Martin visibily emotional.
She went home and from her apartment, she could see the scene.More news: Biden Declares US Will Donate 80 Million Vaccine Doses