Donald Trump is warning the United States' allies they aren't doing their fair share when it comes to global defence.
In his first major policy speech, the Republican frontrunner warned he will abandon NATO and Asian allies if they don't spend enough on defence.
The "America First" speech focused extensively on protecting the US at the expense of other countries.
"Our allies must contribute toward their financial, political and human costs," he said during the speech in Washington, DC.
Trump says the US has grown to be perceived as weak and forgiving, but his policy is being described as potentially damaging to the US' global relationships.
Foreign Policy Group CEO David Rothkopf is stunned at Trump's threat: "Here he is saying things that are actually going to make the alliances upon which we most depend more likely to falter. Because I've got to believe that an ally listening to this is going, 'Oh my God, what do we have in store for us now?'"
Trump delivered his speech a day after sweeping wins in five US primaries and is now calling himself the Republican "presumptive nominee".