Donald Trump has said that the United States has a problem with radical Muslims.

In a typically explosive interview with Fox News' Greta Van Susteren on Sunday night, Trump said that he had friends who were Muslims and great people but made the distinction between moderate and radical Muslims.

"We do have a problem with radical Muslims, there is no question about it," he said.

The comments came as part of a string of questions related to fellow Presidential candidate, Ben Carson, who said that no Muslim should become president of the US.

"I would not advocate that we put a Muslim in charge of this nation," Carson said in an interview with NBC.

"I absolutely would not agree with that."

Carson said he believed it was unconstitutional for a Muslim to be in charge of the US.

Trump, when asked about Carson's comments, said he would not have a problem with voting for a Muslim because there was a thorough vetting process to become a candidate for election.

But Trump was not afraid to lambast the radical wing of Islam, saying it was responsible for terrorism.

"You have [Islamic] radicals that are doing things. I mean, it wasn't people from Sweden that blew up the World Trade Center," Trump said.

The interview came at the end of another controversial week in Trump's campaign after he did not correct a man who said that Obama was a Muslim.

"We have a problem in this country," the man told Trump at a rally. "It's called Muslims. We know our current President is one. You know he is not even American."

Trump defended his decision not to correct the man saying it was not his job to defend the President.