Investors braced for a drawn-out trade war after Donald Trump slapped tariffs on America’s three biggest trading partners, echoing the 2018 economic conflict with China and stoking fears global growth will grind to a halt.

Futures contracts linked to Wall Street and European sharemarket indices positioned for steep losses on Monday after the introduction of a 25 per cent levy on all imports into the US from Canada and Mexico, and a 10 per cent tariff on goods from China.