The Weekly Standard reported that Sessions made the remark in the post-debate spin room in St. Louis on Sunday night.
"This was very improper language, and he's acknowledged that," Sessions said, according to the Weekly Standard.
The publication followed up: "But beyond the language, would you characterize the behavior described in that as sexual assault if that behavior actually took place?"
Sessions replied: "I don't characterize that as sexual assault. I think that's a stretch. I don't know what he meant —"
"So if you grab a woman by the genitals, that's not sexual assault?" asked the reporter.
"I don't know. It's not clear that he — how that would occur," Sessions replied.
In the video first reported by The Washington Post on Friday, Trump says he is "automatically attracted" to beautiful women, and "I just start kissing them. It’s like a magnet. Just kiss. I don’t even wait.”
Trump adds: “And when you’re a star, they let you do it. You can do anything.”
“Whatever you want,” says another voice, apparently that of Billy Bush, then of "Access H0llywood."
“Grab them by the p---y,” Trump says. “You can do anything.”
In a written statement Monday evening, Sessions said: "The Weekly Standard’s characterization of comments I made following Sunday’s Presidential debate is completely inaccurate. My hesitation was based solely on confusion of the contents of the 2005 tape and the hypothetical posed by the reporter, which was asked in a chaotic post-debate environment. I regret that it resulted in an inaccurate article that misrepresented my views. Of course it is crystal clear that assault is unacceptable. I would never intentionally suggest otherwise."
Trump's campaign did not immediately respond to a question about whether Trump agrees with Sessions or not.
At Sunday's debate, moderator Anderson Cooper of CNN told Trump: "You described kissing women without consent, grabbing their genitals. That is sexual assault. You bragged that you have sexually assaulted women. Do you understand that?"
Trump replied: "No, I didn't say that at all. I don't think you understood what was — this was locker room talk. I'm not proud of it. I apologize to my family. I apologize to the American people. Certainly I'm not proud of it. But this is locker room talk."
After repeatedly bring pressed on whether he did the things he talked about on the 2005 tape, Trump eventually said: "And I will tell you: No, I have not."
On Twitter, Sen. Claire McCaskill (D-Mo.) said the comment was "much worse" than when her 2012 Republican challenger, Todd Akin, said "legitimate rape" rarely causes pregnancy. The comment doomed his campaign.
Democrats spent Monday seeking to make Republicans in competitive contests take a position on Sessions's comment.
"Does Toomey Agree with Sen. Sessions That Trump’s Comments Don’t Describe Sexual Assault?" said a news release from the Democratic Senatorial Campaign Committee. Sen. Patrick J. Toomey (R-Pa.) is in a tight reelection race.