The man accused of driving a rental van into pedestrians on a crowded Toronto footpath was charged with ten counts of first-degree murder, as police investigated what motivated the attack.

The attack was Canada's deadliest mass killing in decades. 

Alek Minassian, 25, was also charged with 13 counts of attempted murder for the incident that had the hallmarks of deadly vehicle assaults by so-called Islamic State supporters, but Canadian Prime Minister Justin Trudeau said there was no reason to suspect any national security connection.

Mr Minassian kept his head down during a brief court appearance in Canada's largest city, speaking quietly with a defence lawyer and stating his name when asked to do so.

We need your consent to load this rte-player contentWe use rte-player to manage extra content that can set cookies on your device and collect data about your activity. Please review their details and accept them to load the content.Manage Preferences

Canadian media cited one possible clue to his motive: a Facebook post by Mr Miniassian shortly before the incident that referenced an "incel rebellion", a shorthand used in some online message boards for "involuntary celibacy".

The Toronto Globe and Mail reported the post, citing a spokeswoman for the social media company.

The post also voiced admiration for a man who killed six college students before taking his own life in California in 2014.

Read More
Toronto van attack death toll rises to ten, driver named
Vehicles used as weapons

"The accused is alleged to have posted a cryptic message on Facebook minutes before" the attack, Graham Gibson, a Toronto police detective sergeant, told a news conference.

The majority of the victims were women, ranging in age from their mid-20s to early 80s, Mr Gibson said.

He declined to answer a question about whether anger against women motivated the attack, saying, "that's going to be part of our investigation."

Facebook has since deleted Mr Minassian's account, a representative said.

"There is absolutely no place on our platform for people who commit such horrendous acts," a spokeswoman said in an email.

We need your consent to load this rte-player contentWe use rte-player to manage extra content that can set cookies on your device and collect data about your activity. Please review their details and accept them to load the content.Manage Preferences

Taoiseach Leo Varadkar pledged solidarity with the Canadian people today. 

Speaking in the Dáil, he expressed his condolences over the "appalling attack".

Mr Trudeau called on all Canadians to stand united with Toronto as flowers and messages in multiple languages piled up at a makeshift memorial in the city's north end, an ethnically diverse neighbourhood of towering office buildings, shops, restaurants and homes.

"We cannot as Canadians choose to live in fear every single day as we go about our daily business," Mr Trudeau told reporters outside of parliament in Ottawa.

The prime minister said the incident had not changed the country's threat level or security preparations for a G7 summit in Quebec in June.

Mr Minassian had briefly served in Canada's armed forces in late 2017 but asked to be voluntarily released after 16 days of training, defence ministry spokeswoman Jessica Lamirande said.

He had previously attended a high school programme where one classmate remembered him as "absolutely harmless".

The suspect's two-storey red-brick home in a suburb north of Toronto was declared a crime scene and taped off and surrounded by police vehicles.

Details about the victims began to emerge today, with a South Korean foreign ministry representative saying that two of that country's citizens were killed and one injured in the attack.

The Canadian Broadcasting Corp identified one of the victims as Anne Marie D'Amico, an employee of asset manager Invesco Canada. In a statement, Invesco confirmed that one of its employees had been killed but did not name her.

The attack shook the usually peaceful streets of Toronto, a city with a population of 2.8 million.

The city recorded 61 murders last year.

Canada is still recovering from the shock of a motorway crash in Saskatchewan earlier this month that killed 16 people on a bus carrying a junior hockey team.