Latest: Donald Trump declares new era of competition with ‘America First’ security strategy

The strategy could sharply alter the country’s relationship with the rest of the world.

Update 7.59pm: President Donald Trump has declared a new era of competition is under way with the US set to follow his 2016 campaign doctrine of "America First".

Unveiling the new national security strategy, Mr Trump criticised previous leaders for failing to look out for the nation's citizens.