WASHINGTON – U.S. and Canadian law enforcement are investigating a death threat against America’s ambassador to Canada along with a suspicious “white powder” substance mailed to her residence in Ottawa.

An email sent to all embassy staff say the incident happened around 10:30 yesterday morning after an off-site mailroom supervisor “encountered white powder while screening a letter addressed to the Ambassador,” Kelly Craft.

Fire, RCMP, and a hazardous materials team was immediately dispatched and sealed off a perimeter around the sprawling upscale residence in Ottawa’s East End. The substance has since been deemed not to be harmful.

Along with the powder substance, sources say an expletive-filled letter was also enclosed, threatening to kill the ambassador if she did not resign from her post. The letter also made threatening comments against President Donald Trump.

Sources believe the letter was mailed from Quebec.

Ambassador Craft is said to be “concerned” of the incident.

Former U.S. Ambassador to Canada Bruce Heyman says while ambassadors are threatened in “troubled spots around the world,” he adds, “I did not have that circumstance” while serving in Canada from 2014-2017.

On Twitter, Foreign Affairs Minister Chrystia Freeland expressed support for Ambassador Craft, "following the wholly unacceptable threat made against her."

"She does an essential and difficult job and Canada respects her service," said Freeland.

Diplomatic tensions have escalated between Canada and the United States after President Trump imposed tariffs on Canadian steel and aluminum, and made personal attacks against Prime Minister Justin Trudeau.