As Prime Minister Stephen Harper condemned a wave of deadly attacks on three different continents Friday, Canadian officials said they were trying to determine whether any Canadians are among those killed in a Tunisian resort town.

Early-morning and midday attacks Friday in , , and have left dozens dead. At least 37 people were killed after a gunman opened fire on tourists on the beach in Sousse, a coastal resort town.

Foreign Affairs says more than 800 Canadians were known to be in Tunisia, however the number is only an estimate, since overseas travel registration is voluntary.

Also on Friday, French authorities say one man was decapitated and others injured after an attack on a gas factory in southeast France. And on the same day, an Islamic State group claimed responsibility after a blast at a mosque in Kuwait鈥檚 capital killed at least 16.

Deadly incidents have also rocked parts of Somalia in recent days, as extremist group Al-Shabab vowed to step up attacks during Ramadan.

The PMO said Harper had been briefed by his national security adviser on Friday鈥檚 attacks.

In a statement, the prime minister said he was both 鈥渟addened and angered鈥� to learn of the 鈥渉einous terrorist attacks鈥� in France, Kuwait and Tunisia.

He expressed his condolences to the family and friends of those lost on Friday, and wished those injured a speedy recovery.

Harper added that Canada 鈥渕ourns with France鈥� and stands behind its ally on a 鈥渄ark鈥� day.

鈥淐anadian agencies have reached out and offered French authorities our full support as they bring the perpetrators of this heinous crime to justice,鈥� Harper said.

Harper also said that Canada will fight the 鈥渋nternational jihadist movement,鈥� which has 鈥渄eclared war鈥� on freedom, democracy and human dignity.

鈥淐anada will not sit on the sidelines as this global terrorist group unleashes senseless violence on innocent civilians from Europe to the Middle East.鈥�

In a series of tweets, Foreign Affairs Minister Rob Nicholson also denounced the attacks, saying Canada 鈥渞emains fully committed鈥� to work with the anti-Islamic State coalition to counter global terrorism.

He also commended the African Union Mission in Somalia for their ongoing efforts to bring security and stability to the country.

On Friday, an African Union base in Somalia was also attacked by the al Qaeda-linked extremist group Al-Shabab. Officials say there were many casualties.

Speaking to reporters in Quebec on Friday morning, Opposition leader Tom Mulcair said Canada must give the affected countries the 鈥渟ame strong support鈥� shown to Canada following the attack on Parliament Hill last October.

The NDP leader, who has been a vocal opponent to the Conservative government鈥檚 anti-terrorism bill, also said that Harper shouldn鈥檛 use Friday鈥檚 attacks as an opportunity to infringe upon Canadian rights.

鈥淲e have to be strong and present on the world stage, at the same time we also want to make sure that we鈥檙e protecting our rights and freedoms here in Canada and they should never be sacrificed as Mr. Harper proposes to do with Bill C-51,鈥� Mulcair said.

Canadians in Sousse, Tunisia requiring emergency consular assistance should contact the Embassy of Canada at 216-70-010-200, or call the department's 24/7 Emergency Watch and Response Centre collect at 613-996-8885.

Friends and relatives of Canadians in Sousse should contact Foreign Affairs' emergency response centre by calling 613-996-8885 or 1-800-387-3124. Or they can send an email to sos@ international.gc.ca.

With files from The Canadian Press