A man with no apparent link to Sweden's government has appeared in the role of 'defense and national security advisor' during a political debate on 'The O'Reilly Factor', a television news and current affairs program on Fox News.

During the segment, which focused on the "link" between immigration and crime in Sweden's cities and suburbs, the man, Nils Bildt, spoke about the difficulties of integrating newly arrived immigrants and expressed his desire for the country's leaders to engage in "open and honest" debate about crime.

Swedish publication Dagens Nyheter said Bildt was in fact a company owner in the US who emigrated from Sweden in 1994.

The publication, citing the Arlington General District Court in Virginia, also claimed that Bildt was convicted and sentenced to one year in jail for a crime in 2014.

Marie Pisäter from the Swedish Defense Ministry told the publication there was nobody by the name Nils Bildt working at the organisation, saying: ”We have no spokesman by that name.”

The Swedish Foreign Office also denied Bildt's title, saying: ”We do not know who he is.”

In an email to Dagens Nyheter, Bildt defended his appearance on the program and explained the 'security advisor' title, saying: ”The title was chosen by Fox News's editor – I had no personal control over what title they chose. I am an independent analyst based in the USA."

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A former analyst at the Military Intelligence and Security Service, Johan Wiktorin, told Dagens Nyheter that Bildt "is unknown in Sweden as an expert on national security".

"The depiction of Sweden as a problem country in American media is a disturbing trend,” Wiktorin added.

This episode came after US President Donald Trump's comments last week in which he linked immigration and crime in Sweden, a claim denied by the Sweden's embassy in the US.

My statement as to what's happening in Sweden was in reference to a story that was broadcast on @FoxNews concerning immigrants & Sweden. — Donald J. Trump (@realDonaldTrump) February 19, 2017

@fuadmb About #swedenincident #lastnightinsweden unclear to us what President Trump was referring to,have asked US officials for explanation — Embassy of Sweden US (@SwedeninUSA) February 19, 2017

Swedish Justice and Migration Minister Morgan Johansson hit back at Trump, telling Reuters: "The next time I hope the president, if he's going to speak about Sweden, is better informed about what the conditions really are here."