"The fact of the matter is I've made it clear that if I made anyone feel uncomfortable I feel badly about that", he said.
Biden's remarks were his first public comments since more than a half-dozen women aired their complaints that he had touched them inappropriately at political events.
Flores alleged that Biden had kissed her on the back of her head at a 2014 Nevada rally, a move that made her feel "uneasy, gross, and confused".
Other women have shared similar accounts.
Dingell said, "I'm from the midwest, and I'm going to tell you--I told you for three years... that President Trump could become president because he listened to people in the midwest, he talked about economic issues, he talked about issues that mattered to working people".
But he added: "I´ve had hundreds and hundreds of people contact me - who I don´t know - and say the exact opposite". That's my responsibility - my responsibility and I'll meet it.
"I don't see Joe Biden as a threat", Trump said. I'm not sorry for anything I have ever done.
Biden said he is "very close" to announcing a 2020 presidential bid.
Biden vows to change behavior after allegations of inappropriate touching
Biden, who has yet to definitively announce, is now leading in the polls among Democratic presidential hopefuls, according to RealClear Politics .
Flores wasn't impressed. She tweeted: "To make light of something as serious as consent degrades the conversation women everywhere are courageously trying to have".
Asked whether he could win this Democratic primary given that he's been tagged as a moderate by many activists in the party, Biden dismissed that label.
With almost 50 years in public life, Mr. Biden said that his record speaks for itself.
He pledged the concerns would change how he campaigns should he run for president.
Friday was the second time in two days the president attacked Biden on Twitter.
When a reporter asked him what the hold up was, Biden responded, "Putting everything together, man. Putting everything together".
"I think I'm a very good messenger, and people got a kick out of it", Trump told reporters before leaving the White House for a trip to the US-Mexican border.