Donald Trump has said he accepts the view of US intelligence that Russia is continuing to meddle in elections.
The president told a television interview that he has "tremendous faith" in Dan Coats, director of national intelligence, and that he would "accept" his conclusions on Russian involvement.
He also said he had warned Vladimir Putin to stay out of American elections. "I let him know we can't have this," he said of the pair's meeting in Helsinki on Monday. "We're not going to have it, and that's the way it's going to be."
The admission is the latest in a series of reversals in Mr Trump's assessment of Vladimir Putin and Russian meddling.
When asked by reporters a few hours earlier if the US was still being targeted by Russia, he had answered "no". This was a belief that put him at odds with his intelligence chiefs.
But White House press secretary Sarah Sanders said hours later that she had talked with the president and he had instead been saying "no" to taking further questions from reporters.
When asked if she was reversing what the president had said, she answered: "I'm interpreting it, not reversing it."
The White House has struggled to contain the fallout from a news conference from Helsinki, in which Mr Trump, standing next to Mr Putin, said he "didn't see any reason" why Russia would be involved in US election meddling.
The basis for the assessment, despite what he said was "great confidence" in his intelligence agencies, was that Mr Putin had given an "extremely strong and powerful" denial.
The comments prompted bipartisan bemusement and fury. The next day, Mr Trump claimed he had misspoke, and had intended to say he did not see any reason why Russian wouldn'tbe responsible for interfering in the 2016 vote.
"In a key sentence in my remarks I said the word 'would' instead of 'wouldn't'," he said.
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"I thought it would be obvious but would like to clarify in case it wasn't."
In the Wednesday interview Mr Trump continued with his changing assertions, saying he would hold Putin personally responsible for future election interference.