President Donald Trump is focused on crushing overseas automakers with heavy tariffs, now seeing the threat of further car duties as his best trade negotiating tactic, Axios reported Monday.

The president has told aides privately that his perceived trade deal success in Canada was because of threats to Prime Minister Justin Trudeau that the U.S. would levy painful auto tariffs, Axios reported. Trump is now reportedly considering using the same tactic with the European Commission.

"Trump says gleefully that the moment he started talking about maybe tariffs on cars, that [European Commission President Jean-Claude] Juncker got on the fastest plane known to mankind, comes straight over to Washington and starts offering deals," a senior European official told Axios.

GM and Ford shares were up fractionally Monday morning. Tariffs would be negative for the companies if other countries decided to retaliate.

Read the full Axios report here.

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