(Reuters) - U.S. Republican presidential candidate Donald Trump said on Tuesday that “most likely I won’t be doing the debate” on Fox News in Des Moines, Iowa, scheduled for Thursday night. The billionaire businessman made the comment at a news conference in Marshalltown, Iowa, as the nomination race nears its first contest, the Iowa caucuses, on Monday. Trump has been engaged in a public spat with Fox News since a debate last August in which he said he was subject to unfair questioning by moderator Megyn Kelly.  “Let’s see how much money Fox makes without me in the debate,” Trump told the news conference.  (Reporting by Eric Walsh in Washington; Editing by Eric Beech) SAP is the sponsor of this coverage which is independently produced by the staff of Reuters News Agency.