“We believe that the threat still exists,” she said, “which is why we are taking steps to prevent it.”

It was the second day of reversals and semantic hairsplitting in Mr. Trump’s statements about Russia — on Tuesday, he said that he had meant to say at a news conference in Helsinki that he disagreed with a statement by Mr. Putin, not that he agreed with it — and it only deepened the mystery of what exactly Mr. Trump and Mr. Putin had talked about during a two-and-a-half-hour session in Finland when only their interpreters were in the room with them.

Democrats demanded that Mr. Trump’s State Department interpreter be summoned to Capitol Hill to testify about what the president said, a prospect that seemed unlikely, given the lack of Republican support. But Republicans also hardened their criticism of Mr. Trump, with lawmakers expressing anger and incredulity at his shifting statements.

Mr. Trump has been consistent in some respects. In his CBS interview, he delivered yet another broadside against prominent veterans of the intelligence community, referring to a former director of the C.I.A., John O. Brennan, as a “total lowlife,” and suggesting that someone had gotten to James R. Clapper, a former director of national intelligence.

But Mr. Trump tried to dispel perceptions of a rift between him and the current national intelligence director, Dan Coats, who has warned of Russia’s continuing efforts to meddle in American elections. Mr. Trump said Mr. Coats was doing an “excellent job,” as was the C.I.A. director, Gina Haspel.