National security adviser John Bolton confirmed on "Fox News Sunday" that a Trump administration official signed a document pledging to pay North Korea a $2 million hospital bill to release Otto Warmbier, though he said no money was ultimately transferred.

WALLACE: Did North Korea demand money for the release of Otto Warmbier?

BOLTON: It appears that they did. This occurred before I came into the administration, but that's my understanding.

WALLACE: Did the U.S. official who was there to get him out of the country, Joseph Yun, did he sign a document pledging the money in order to get him out.

BOLTON: That is what I am told, yes.

WALLACE: I guess the bottom line question is, did the U.S. pay any money to North Korea, however it was disguised, after Warmbier was released?

BOLTON: Absolutely not. And that's the key point.

The backdrop: President Trump called the Washington Post story that first reported the hospital bill "fake news," though the report notably said it was "unclear" whether the administration actually ended up paying the bill. Nothing in the story has been proven inaccurate.