A Calgary man is now one of the United States’ most-wanted terrorists.

Farah Mohamed Shirdon left Canada to join ISIS a few years ago, and made international headlines when he burned his passport and threatened both Canada and the U.S. in a video in 2014.

“We know he made threats towards beheading President Obama at the time and raising the ISIS flag above the White House,” said Michael Zekulin, University of Calgary professor. “The fact he's being added to this list now, are they doing their due diligence or they may have credible intelligence about where he is and what he’s up to.”

Police believe the former Calgarian who was born in Toronto travelled to Iraq and Syria to train and fight in 2014. A year later, RCMP laid terrorism charges in absentia because they believed Shirdon was still overseas.

“Spreading the ideas and reaching back into Canada and attracting more people, that becomes a concern and to put him on the list is to prevent him from arriving here,” said Zekulin.

A second Canadian added to the list, Tarek Sakr, is a Syrian-born Canadian who conducted sniper training and is linked to Al Qaida's affiliate in Syria.

Shirdon is not the first Calgarian to become radicalized and join the terror group. Damian Clairmont and Salman Ashrafi were killed while fighting for ISIS.

Zekulin said the names on this latest list will be shared with counter-terrorism officials around the world.