A week ago, the Dutch driver was believed to have been referring to Garry Connelly when he said a steward who repeatedly penalises him was a “mongol” and “idiot”.
He withdrew the ‘mongol’ insult, but amid reports the FIA wanted an apology, Verstappen stood by the other criticism.
“When you are unjustly taken off the podium after a race, it seems normal to me that you are angry,” Verstappen is quoted by Algemeen Daghblad newspaper.
“Unfortunately I cannot change the word that I used.”
F1 race director Charlie Whiting, however, hit back at the suggestion that one steward was responsible for the decision, saying all four officials in Austin voted for the penalty.
And he added: “Until now Max has not apologised. But it would be good if he did.”
Verstappen later wrote on Instagram: “I once again apologise for the language that I used following the US grand prix.
“I know that the words I used were inappropriate and they were not directed at any one person.”