Republican US presidential front-runner Donald Trump has vowed to pursue an "America First" foreign policy if elected, saying many nations including allies "ripped off" America, while China has rebuilt itself from money that it has "drained out of the US".
Expounding his foreign policy priorities, Trump said he would consider pulling out American troops from Japan and South Korea if the close allies did not pay the US more.
Trump told the New York Times that he might stop buying oil from Saudi Arabia if it did not send troops to back US efforts to fight Islamic State (IS) militants.
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The 69-year-old real estate billionaire, who has kept his momentum rolling despite concerted efforts by party establishment to thwart his presidential aspirations, insisted he was "not isolationist" but "America First".
He said, "We have been disrespected, mocked, and ripped off for many, many years by people that were smarter, shrewder, tougher. We were the big bully, but we were not smartly led. And we were the big bully who was the big, stupid bully and we were systematically ripped off by everybody."
"So America first, yes, we will not be ripped off anymore. We're going to be friendly with everybody, but we're not going to be taken advantage of by anybody," he said.
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Trump cited the US debt — "soon to be $21 trillion" —and linked it to the fact the US "defended the world".
"No matter who it is, we defend everybody. When in doubt, come to the United States. We'll defend you. In some cases free of charge."
He said that China, now the world's second largest economy after America, had rebuilt itself from money that has "drained out of the United States".
"They've done it through monetary manipulation, by devaluations. And very sophisticated. I mean, they're grand chess players at devaluation," Trump said.
He added: "I like China very much, I like Chinese people. I respect the Chinese leaders, but you know China's been taking advantage of us for many, many years and we can't allow it to go on.”
Talking about the rise of China, he said the best way to halt Beijing's building of military airfields and anti-aircraft batteries on reclaimed islands in the disputed South China Sea was to threaten its access to American markets.
"We have tremendous economic power over China, and that's the power of trade," he said.
He declined to elaborate on his plans for dealing with the Communist giant, saying "I wouldn't want them to know what my real thinking is."
Trump said the US was "not being properly reimbursed" for protecting Saudi Arabia.
"Without us, Saudi Arabia wouldn't exist for very long. It would be, you know, a catastrophic failure without our protection.
"They're a money machine... And yet they don't reimburse us the way we should be reimbursed.