COLLEVILLE-SUR-MER, France — With marble crosses and Stars of David marking the graves of those who died fighting the Nazis on D-Day visible in the background, President Trump used the occasion of the 75th anniversary of the invasion of Normandy to bash the special counsel, Robert S. Mueller III, in an interview with Fox News.

“He made such a fool out of himself,” Mr. Trump told the interviewer, Laura Ingraham, in a discussion taped minutes before the president stepped onto the dais with a few dozen surviving D-Day veterans on Thursday.

His remarks about Mr. Mueller, a decorated military veteran who served in Vietnam, were not particularly surprising on their own — Mr. Trump has been criticizing him for months.

But Mr. Trump chose to renew his attack on the man who oversaw the investigation into Russian election interference in an interview carved out shortly before a solemn occasion: the commemoration of one of the most consequential military victories in American history.