Donald Trump launched a blistering attack on “chronic trade abuses” on Friday, warning an audience of world leaders at a summit in Vietnam that he will always “put America first”.

The US president also resumed his tough talk on North Korea as he sought to rally Asia-Pacific nations into confronting the “twisted fantasies” of Pyongyang’s young leader Kim Jong-un.

Mr Trump was speaking to a gathering of CEOs at the Asia-Pacific Economic Cooperation summit in the city of Danang after arriving from a three-day visit to Beijing were he had softened his tone on trade and North Korea.