Mohawks gather near the Seaway International Bridge to protest the arming of border guards (Rebecca Zandbergen/CBC)Canadian authorities shut down a border crossing into the United States at Cornwall, Ont., Monday morning after Mohawk leaders from the nearby Akwesasne territory warned they would not tolerate guns in their community.

Talks on the weekend between Mohawk officials and the Canadian Border Services Agency broke down over the issue of arming guards assigned to posts on Cornwall island, which is in the middle of Akwesasne, a territory that straddles Quebec, Ontario and New York State.

The border guards in Cornwall were set to start carrying 9-mm handguns Monday morning, under a new federal policy enacted across the country. Instead, guards left their posts at midnight Sunday, citing safety concerns, after hundreds of Mohawks set up camp near the border to protest the gun policy.

John Boots, a Mohawk from Akwesasne, says border guards are 'nasty' to his people (Rebecca Zandbergen/CBC)Border authorities later closed the border altogether, allowing no vehicles to cross the Seaway International Bridge.

The Mohawk protesters are angry about guards being allowed to carry guns, because they say it violates their sovereignty, and increases the likelihood of violent confrontations.

"Their biggest fear is that because of the animosity that exists right now, that one of them young people that has guns in there [and] three weeks of training, probably no psychological testing either – that one of them is going to lose it in there and kill one of our people," said Cheryl Jacob, district chief at the Akwesasne Mohawk Council.

Hundreds of protesters near the border crossing gathered around a bonfire and held signs that said "Guns kill," "This is Mohawk land" and "Honk for no guns," said the CBC's Lauren McCallum, reporting from the scene.

The Mohawk protesters reportedly cheered when news of the border guards' departure became known.

Protesters built a bonfire near the customs border crossing office (Lauren McCallum/CBC)"They're so nasty and harassing our people that we can almost feel ... their finger being itchy on the trigger," said John Boots, a Mohawk from Akwesasne. "That's how bad those people are. The customs officers."

"We're no more of a threat today than we were yesterday," said Anenhaienton, another Akwesasne resident. "So, why all of a sudden do they need guns?"

Boots warned that people are not going to back down from the issue. "If they say they're going to arm the guards, we're going to stay here, and we're going to stop them whenever we see them coming," he said.

It's not clear when the blockade would end and the border reopen.

People who "want to leave the reserve are allowed to leave, but they're not allowed to return" for as long as the conflict lasts, said Cornwall police staff Sgt. Pierre Pilon.

Public safety minister Peter Van Loan said the gun policy will be applied to all Canadian border crossings, with no exceptions.