Barack Obama believes Donald Trump will not be president

WASHINGTON: US President Barack Obama believes Republican White House hopeful Donald Trump would not be elected as his successor as being a president is tougher than hosting a reality show and Americans are too "sensible" to elect him.

"I continue to believe 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 recognise that being President is a serious job," Obama told reporters after the first ever US-ASEAN Summit in Sunnylands, California.

"It's not hosting a talk show or a reality show. It's not promotion. It's not marketing," he said.

The 69-year-old billionaire real estate tycoon fired back, saying Obama was lucky that he did not run for office in 2012.

"You're lucky I didn't run last time when Romney ran because you would have been a one-term president," Trump said at a campaign rally in South Carolina.

Obama also criticised other Republican candidates.

He said he thinks foreign observers are troubled by some of the rhetoric that's been taking place in these Republican primaries and Republican debates.

"I don't think it's restricted, by the way, to Mr Trump. I find it interesting that everybody is focused on Trump, primarily just because he says in more interesting ways what the other candidates are saying, as well," he noted.

"He may up the ante in anti-Muslim sentiment, but if you look at what the other Republican candidates have said, that's pretty troubling, too," Obama said.

The president said Trump was not the only Republican who raised concerns, but he singled out the real estate mogul as someone who would be singularly unprepared for the responsibilities of the Oval Office.

In an apparent reference to another Republican presidential aspirant Marco Rubio, the Senator from Florida, Obama said there is a candidate who sponsored a bill, which he supported, to finally solve the immigration problem, and he's running away from it as fast as he can.

Observing that all Republican candidates are denying climate change, Obama said he this that's troubling to the international community, since the science is unequivocal.