The current US leader does not think his Republican rival is up to the job.

Republican frontrunner Donald Trump will not be president because it’s a “serious job”, President Barack Obama has said.

“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,” said Mr Obama.

The controversial, billionaire businessman, is currently the favourite in the race to be his party’s choice for the Oval Office.

He is currently leading the polls in South Carolina – where Republicans vote on Saturday – after flattening his rivals in last week’s New Hampshire primary.

However, the current president doesn’t believe the controversial mogul is up to the job.

Voters will not choose Mr Trump, because “they recognise that being president is a serious job”, claimed Mr Obama – who last week sent a touching Valentine’s to the LGBT community.

“It’s not hosting a talk show or a reality show, it’s not promotion, it’s not marketing, it’s hard,” he said at the Asean economic summit in California.

“It’s not a matter of pandering and doing whatever will get you in the news on a given day.”

Rather than take offence, Mr Trump said it was a compliment to be criticised by a president who had done so much damage to the country.

Elsewhere this week, Donald Trump declined to rule out a conspiracy theory that conservative Supreme Court justice Antonin Scalia was secretly murdered by liberals, after he died from a suspected heart attack.

Speaking to a right-wing radio host, Mr Trump appeared to pander to the host’s theory that Justice Scalia was murdered.

Mr Trump said: “I’m hearing it’s a big topic, the question… it’s a horrible topic.

“They say they found a pillow on his face. It’s a pretty unusual place to find a pillow.”

It was also revealed that a third of Donald Trump supporters want to ban gays from entering the United States – as well as Muslims.