Canadians and their political leaders joined the rest of the world in expressing shock and outrage over the deaths of dozens of people in Nice, France, after a man driving a truck loaded with weapons plowed into a crowd of people on Thursday.

Speaking in Calgary on Friday, Prime Minister Justin Trudeau sent condolences to the people of France on behalf of all Canadians.

"Our hearts go out to all the victims and their families. Canada stands with France as a steadfast ally and we will work with the international community to fight terror and to ensure that we live in a peaceful world," he said.

Trudeau had also offered "sympathy" to the victims in a tweet sent Thursday and added in a statement that Canada has offered "all possible assistance to the French government."

"Senseless acts like this one are not isolated events, and we will continue to work with our allies and partners to fight terrorism in all of its forms."

Foreign Affairs Minister Stéphane Dion also issued a statement late Thursday saying Canada condemns this "horrific terrorist attack."

"We offer our deepest condolences to the families and friends of those killed and a speedy recovery to those injured. Canadians are deeply saddened by this tragedy and we stand in solidarity with the people of France on their national day."

Dion said the Canadian consulate in Nice is in contact with local authorities and the Emergency Watch and Response Centre in Ottawa is "active and assisting Canadians."

British Columbia Premier Christy Clark also tweeted that the incident is "just horrible."

"Thinking of all those involved and their families," she wrote.

Alberta Premier Rachel Notley said "all Albertans are heartbroken for the families of those killed and injured in tonight's senseless attack in Nice. We stand in solidarity with the people of France."

Federal Opposition leader Rona Ambrose and NDP Leader Thomas Mulcair also expressed their shock as did former prime minister Stephen Harper.

"The people of France are in our thoughts this evening, following the terrorist attack. I pray for the victims and their families," Harper tweeted.

Conservative MP Maxime Bernier also tweeted about the "horror."

"We stand with France and the French in the fight between civilization and barbarism," he wrote.

The truck, which was carrying grenades and other weapons, drove on to a sidewalk and plowed through a crowd of Bastille Day revellers who'd gathered to watch fireworks in the French resort city late Thursday.

French officials said 84 people, and 18 are in critical condition.

They said the truck plowed into the crowd over a distance of two kilometres near Nice's Palais de la Méditerranée, a building that fronts the beach.

Canadian residents were also starting to mark the safe option on Facebook's "Safety Check."

Alex Mitchell, who lives in Kingston, Ont., wrote in an email that he and his family are staying in an apartment a few blocks from the scene.

He said they were already back from watching the fireworks when the news broke.

"What Val and I keep thinking about is all the families and children we saw tonight— and there were so many," he said, referring to his wife. "To think that such a wonderful event could be turned into something so horrible makes us both sick. We're just not sure what to tell our kids."

A group of high school students from Nanaimo, B.C., was also reported "safe and accounted for" in posts on Facebook and Twitter by their school district.

Doug White, a councillor with the Snuneymuxw First Nation, wrote on his Facebook page that his niece was on the trip.

"I can't take the stress — my niece Isabella texted me to tell me she and her friend ran across Nice to get away from the horrible Bastille Day attack in Nice, France to get to the home they are staying at..." he posted. "She is OK and all the kids from Nanaimo that are over there are OK — thank god!"

Another person, Aman Cheema, simply tweeted: "Hey guys me and my wife are safe, we were just two blocks away from the attack."

Images being broadcast across French media showed people running for their lives down Nice's Promenade des Anglais, the famous seaside boulevard named for the English aristocrats who proposed its construction in the 19th century.

It was not immediately clear who would have been behind the attack, but France has recently seen a spate of dramatic assaults from by jihadist groups, including the Islamic State of Iraq and Syria.

With files from CBC News