The top federal prosecutor in Manhattan said on Monday that Britain’s Prince Andrew has “shut the door” on helping an investigation into allegations of sex trafficking by the financier Jeffrey Epstein and his associates.

It was the second time in less than two months that the prosecutor, Geoffrey S. Berman, has taken the unusual step of publicly pointing out that Prince Andrew has refused to cooperate with the inquiry despite saying he was willing to.

“Prince Andrew has now completely shut the door on voluntary cooperation,” Mr. Berman, the United States attorney in Manhattan, said in response to a question at a news conference on an unrelated matter on Monday. Mr. Berman added that his office was “considering its options,” without elaborating.

In January, responding to a similar question, Mr. Berman had said that Prince Andrew had provided “zero cooperation” in the investigation.