OTTAWA -- The menace posed by the Islamic State is the conflict that keeps Canada's new top military commander awake at night.

Gen. Jonathan Vance, who took over as the country's 19th chief of defence staff on Friday, says the rise of an extremist state in the Middle East is not something that can go unchallenged by the West.

Vance, in an interview with The Canadian Press, said countries in the region that are trying to develop democratic institutions and the rule of law cannot do so with a caliphate, bent on exporting terror, smack in the middle of them.

His geo-political take stands in contrast to recent comments by the incoming chairman of the U.S. Joint Chiefs of Staff, marine Gen. Joseph Dunford, who described a resurgent Russia as the biggest threat.

Dunford told his confirmation hearing before the U.S. Congress last week that Vladimir Putin's regime is a nuclear power with the capability of violating the sovereignty of other nations, and whose actions have been alarming.

Vance says Canada's contribution to checking Russian ambitions is eastern Europe is significant and will remain so, but the Islamic State has shown its willingness to create terror on Canadian soil.