Royal Canadian Mounted Police spokesman David Falls said Monday that the suspect "was known to Federal authorities" and "authorities were concerned that he had become radicalized." Canadian Prime Minister Stephen Harper was briefed about the incident by the head of Canada's national police force, the head of the military and his national security adviser. "First and foremost our thoughts and prayers are with the victims and their families; we're closely monitoring the situation and obviously we will make available all of the resources of the federal government," Harper said. Images of Michael Adebolajo, 29, holding a butcher knife and cleaver with bloodied hands in the moments after the May 2013 killing of Fusilier Lee Rigby shocked people around the world and sparked fears of Islamist terrorism in Britain. The Islamic State group has urged supporters to carry out attacks against Western countries, including Canada, that are participating in the U.S.-led coalition fighting the militants who have taken over large swaths of territory in Iraq and Syria.