Fox news presenter Megyn Kelly expressed her frustration on air when an update on the Ferguson riots interrupted an interview about the death of American journalist James Foley.

An Isis video released overnight on Tuesday shows a suspected British jihadist beheading Foley in what is claimed to be a revenge killing for the ongoing US air strikes in Iraq.

When breaking news from Ferguson appeared on the screen during her covergae on Tuesday night, Kelly said: “Hold on…I realise… I realise something is happening in Ferguson, but we’re talking about something important here, so can you at least split screen the video.”

“The protesters and the police are clashing again, they’re clashing again. But we’re talking about the dead, the death of an American who was beheaded.”

On Wednesday officials confirmed that a US Special Operations mission tried and failed to free Foley and other hostages in Syria weeks before he was murdered by militants.

But Obama said America would not be deterred from carrying out airstrikes against the group.

In pictures: James Foley Show all 11 1 /11 In pictures: James Foley In pictures: James Foley James Foley Freelance photo-journalist James Foley (left) on the highway between the airport and the West Gate of Sirte, Libya AFP In pictures: James Foley James Foley James Foley responds to questions during an interview with The Associated Press, in Boston AP In pictures: James Foley James Foley James Foley responds to questions during an interview with The Associated Press, in Boston AP In pictures: James Foley James Foley James Foley at an airport in Tripoli (Libya), August 2011 Jonathan Pedneault via freejamesfoley.org In pictures: James Foley James Foley James Foley in Syria, 2012 Manu Brabo via freejamesfoley.org In pictures: James Foley James Foley James Foley in Aleppo, Syria, in 2012 Nicole Tung via freejamesfoley.org In pictures: James Foley James Foley James Foley rests in Syria, 2012 Manu Brabo via freejamesfoley.org In pictures: James Foley James Foley US photo-journalist James Foley resting in a room at the airport of Sirte, Libya. Jihadist group the Islamic State claim to have executed American journalist James Foley in revenge for US air strikes against its fighters in Iraq AFP In pictures: James Foley James Foley Badges in support of James Foley displayed during a panel discussion about the importance and dangers of reporting on world conflicts at a Free James Foley event on 3 May 2013 in Boston. At the time, Foley, a freelance journalist, had been held in captivity in war-torn Syria for 162 days AFP PHOTO/Don Emmert In pictures: James Foley James Foley John and Diane Foley, parents of James Foley, at a Free James Foley event on 3 May, 2013 Getty In pictures: James Foley James Foley A ribbon is tied to a tree outside the home of American freelance journalist James Foley in Rochester, N.H AP

Kelly's remarks came on the same evening that she criticised Missouri Governor Jay Nixon after he issued a statement in which he suggested that the officer responsible for fatally shooting black teenager Michael Brown in “broad daylight” should face a “vigorous prosecution”.

In a videotaped statement on Tuesday, former Attorney General Nixon said: “We have a responsibility to come together and do everything we can to achieve justice for this family; a vigorous prosecution must now be pursued.”

Kelly repeatedly slammed the “irresponsible and outrageous” statement, saying that Nixon had ignited a “firestorm” by “decid[ing] the guilt of the officer in this case long before any investigation is completed”.

In his statement Nixon emphasised his wish to seek “justice for the family of Michael Brown”. Two autopsies have shown that the 18-year-old was struck by six bullets fired by Darren Wilson, 28, on 9 August in Ferguson, St Louis.

Video: The latest from Ferguson

Kelly is well-known for making clear her views on air and has incited controversy in the past. In December last year Kelly was forced to defend herself after claiming Santa was white – “[he] is what he is” - in response to an article by Aisha Harris that said the festive figure should appeal to all races.

And in July Kelly was accused of backpedalling women’s rights by opposing late-term abortions carried out for health reasons.