Dhaka, May 25 -- US President Donald Trump threatened on Friday to ratchet up his trade war again, pushing for a 50 per cent tariff on European Union goods starting June 1 and warning Apple he may slap a 25 per cent levy on all imported iPhones bought by US consumers.

The twin threats, delivered via social media, roiled global markets after weeks of de-escalation had provided some reprieve in the tariff battle. Major US stock indexes and European shares fell and the dollar weakened, while the price of gold, a safe-haven for investors, rose. US Treasury yields fell on fears about tariffs' effect on economic growth, reports Reuters.

Trump's broadside against the EU was prompted by the White House's belief that negotiations with the bloc a...