Kenyan troops were in the final stages Monday night of securing the Nairobi shopping mall seized by al Qaeda-linked militants -- two days after gunmen seized the mall, taking a number of hostages and leaving at least 62 dead.

A series of explosions followed by torrents of gunfire rocked Westgate Mall throughout the day, as security forces ramped up their efforts to gain control of the plaza that became the scene of the horrific attack.

Security forces said most or all hostages had been released by Monday night.

Officials estimate between 10 and 15 gunmen carried out the attack, including at least one who was dressed as a woman.

Kenya’s Foreign Minister Amina Mohamed said "two or three Americans" and "one Brit" were among the militants who stormed the mall Saturday.

In an interview with PBS, Mohamed said the Americans were 18 to 19 years old, of Somali or Arab origin.

U.S. officials said Monday they were looking into whether any Americans were involved in the brutal attack.

Canada’s Department of Foreign Affairs is also probing reports that a 24-year-old from Ontario is among the gunmen.

Three of the gunmen who stormed the mall were killed by Kenyan security forces, and officials said more than 10 suspects were arrested.

Eleven Kenyan soldiers were wounded in the running gun battles.

According to the Kenyan Red Cross the attack left at least 62 dead and dozens more injured. An earlier death doll of 68 was lowered after officials said some bodies had been counted twice.

Among the dead were two Canadians: diplomat Annemarie Desloges, 29, and Vancouver businessman Naguib Damji, 59.

Hodan Hassan of Minnesota told CTV News that her two nieces, who were born in Toronto, both suffered injuries in the attack.

Hassan said Fardosa Abdi, 17, and Dheeman Abdi, 16 were inside Westgate Mall Saturday when gunmen stormed the building and began firing at shoppers.

She said Fardosa suffered severe leg injuries and has already undergone two surgeries and two blood transfusions, while Dheeman suffered a gunshot wound to the leg and arm injuries caused by an explosion.

“We’re just praying and hoping she’ll be fine,” Hassan said.

By Monday evening, Kenyan security officials claimed they had taken control of the mall.

"Taken control of all the floors. We're not here to feed the attackers with pastries but to finish and punish them," Police Inspector General David Kimaiyo said on Twitter.

CTV’s Middle East Bureau Chief Martin Seemungal said by Monday night there was a growing “confidence” that Kenyan security officials were in control of the mall.

“One military official is going as far to say all the militants have been killed,” he told CTV News from Nairobi.

Seemungal said officials have yet to indicate how many hostages have been freed since the rebels stormed the mall.

“We never really got a sense if they were all rescued safely,” he added.

Officials confirmed that both Kenyan and foreign nationals were among the dead, including citizens of the United Kingdom, France, India, South Africa, China and Ghana.

Al-Shabaab said the attack was in retribution for a 2011 military operation during which Kenyan soldiers moved into Somali territory.

Bronwyn Bruton, the deputy director of Washington D.C.-based Africa Center, says the Nairobi attack was essentially a suicide mission that signifies a “new phase” in the al-Shabaab organization.

“The fact that they could deploy 10 to 15 people on a suicide mission like that, requiring such discipline and co-ordination, is a very frightening indication of their capacity,” Bruton told CTV’s Power Play on Monday.

She described al-Shabaab as a “brutal” insurgency that’s primarily focused on overthrowing Somalia’s Western-back government.

“It’s an African rebel group, so it certainly brings the tradition of brutality, of harming innocent civilians, of ruling through terror. And then on top of that, al Qaeda is obviously one of the most feared organizations in the world and brings another set of tactics that is truly terrifying,” she said.

“And what you have in al-Shabaab is essentially a merger of those two traditions.”

With files from The Associated Press