WATCH: Prime Minister takes a lengthy pause when asked about Trump

Canadian Prime Minister Justin Trudeau says Canadians are watching what's unfolding in the United States with ``horror and consternation'' and he paused for 21 seconds when asked about U.S. President Donald Trump and the use of tear gas against protesters to clear the way for a photo opportunity.

Trudeau has long been careful not to criticize Trump as Canada relies on the U.S. for 75 per cent of exports.

But Trudeau, who is usually quick to answer, struggled to come up with the right words when asked about Trump calling for military action against protesters and the use of tear gas for a photo opportunity.

The prime minister avoided mentioning Trump directly.