Shares in some of the biggest European carmakers slumped on Monday after U.S. President Donald Trump imposed new tariffs of 25% on goods from Mexico and Canada and 10% on imports from China, raising concern over possible duties on EU imports too.

The threat of a transatlantic trade war loomed large Monday over a gathering of European leaders aimed at boosting the continent's defences in the face of an aggressive Russia. The EU's 27 leaders convened the Brussels talks involving Britain'