WASHINGTON — President Trump has no intention of releasing his tax returns, his senior counselor said on Sunday, ruling out a step he had said he would take once an Internal Revenue Service audit was completed.

“The White House response is that he’s not going to release his tax returns,” the counselor, Kellyanne Conway, said in an interview on the ABC program “This Week.”

“We litigated this all through the election,” she added.

Last year, Mr. Trump became the first major-party presidential nominee in more than 40 years not to release his tax returns, and he would be the first president since the early 1970s to decline to release tax information, either through a summary or a full or partial return.

While Ms. Conway said that Mr. Trump had complied “with all the ethical rules” and “done everything” he needs to do to step away from his businesses, many ethics experts have taken the opposite view. They argue that Mr. Trump has not done enough to separate himself from his business empire and guarantee that he will not be subject to conflicts of interest while in office. They continue to call for the release of his tax returns as a way of evaluating potential areas of conflict.