Obama did not limit his criticism to the billionaire real estate tycoon, hitting out at 'troubling' statements from the entire GOP field of candidates seeking to replace him.

But he reserved his toughest remarks for Trump, offering a scathing assessment of why he thinks the American people will not elect him.

"I continue to believe that Mr Trump will not be President. And the reason is because I have a lot of faith in the American people. And I think they recognize that being president is a serious job," he told reporters in California yesterday.

"It's not a matter of pandering and doing whatever will get you in the news on a given day. And sometimes it requires you making hard decisions, even when people don't like it," Obama continued.

He also noted the need to be "able to work with leaders around the world in a way that reflects the importance of the office."

"The American people are pretty sensible. And I think they'll make a sensible choice in the end," he concluded.

The 69-year-old Trump has long been ahead in the Republican race for the White House nomination, according to opinion polls.

He lost the Iowa caucuses to Senator Ted Cruz early this month, but roared to victory in the New Hampshire primary last week. He holds a commanding 16-point lead over Cruz in South Carolina, according to a CNN poll.

Obama, whose successor will be chosen on November 8, insisted that Trump was not alone in expressing unsettling proposals on the Republican campaign trail.

Read more: Donald Trump threatens to sue Ted Cruz

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