Washington DC, Sept. 7 -- US President Donald Trump signalled a sharp escalation in cross-border trade friction on Monday, declaring that Canadian aircraft manufacturer Bombardier should be banned from selling its jets in the United States unless the company shifts manufacturing operations to American soil.

In a Truth Social post, Trump attacked the Montreal-based business jet maker and accused Ottawa of enforcing protectionist policies against American firms.

"NO MORE SELLING BOMBARDIER IN THE UNITED STATES! Their products aren't good enough!" Trump wrote. "Over 50% of their revenue comes from the United States - They live off American Buyers, American Companies, American Airports, and American Service - All while Canada blocks our GRE...