Trump 'doesn't know why' he's lost lead in poll
Donald Trump can't believe he has lost the lead in the race for US Republican presidential nomination.
The latest New York Times/CBS News survey shows neurosurgeon Ben Carson is sitting in front of the billionaire businessman, leading 26 percent to 22.
Mr Carson's success is being attributed to his large support base in the Midwest.
US correspondent Sandy Hughes told the Paul Henry programme Mr Trump can't come to terms with it.
"Ben Carson's doing very well in Iowa," she says. "This morning Donald Trump's answer to that was, 'Well, I just don't understand that', he doesn't know why he's not doing well in Iowa."
Watch the video for the full interview with Sandy Hughes.