– President Donald Trump aggressively returned to the issue of sexual harassment Tuesday, again dismissing his own accusers as fabricators and attacking a female Democratic senator as a "lightweight" who "would do anything" for campaign contributions.

The president's attacks came in early morning Twitter posts after three of the accusers had come forward Monday to renew their charges from last year that Trump had sexually assaulted them before he entered politics, and after Sen. Kirsten Gillibrand, D-N.Y., had called for him to resign.

While Trump weathered the accusations during his presidential campaign, the flood of recent allegations against powerful men has revived the issue of sexual harassment with a newfound fury. By inserting himself directly into the discussion, the president ensured that calls for renewed scrutiny of the women's allegations would gain new energy and prominence.

Gillibrand was quick to fire back. "It was a sexist smear attempting to silence my voice, and I will not be silenced on this issue," she said. "Neither will the women who stood up to the president yesterday," she added.

Gillibrand first learned of the president's Twitter post while she was attending a bipartisan Bible study, one of her aides said. The aide also said that Gillibrand had met with Trump just once in his office, several years ago, and that his daughter Ivanka was at the meeting.

"Lightweight Senator Kirsten Gillibrand, a total flunky for Charles E. Schumer and someone who would come to my office 'begging' for campaign contributions not so long ago (and would do anything for them), is now in the ring fighting against Trump," the president tweeted.

Sen. Mike Rounds, R-S.D., who said he was at the Bible study when the tweet was sent, said, "I think this is simply one of those cases where it is best if we look at what the president does and not pay attention to the tweets."

Sarah Huckabee Sanders, the White House press secretary, later denied that Trump's tweet contained a sexual reference, saying that he was referring to general corruption in the U.S. political system.

Asked whether the president would apologize to people who read the tweet as sexual innuendo, Sanders said he would not. "Only if your mind is in the gutter would you have read it that way," she said.

"He's not alleging anything. He's talking about the way that our system functions as it is," Sanders said at a White House news conference. "That comment, frankly isn't something new."

Senate Democrats, including Gillibrand, forced the resignation last week of Sen. Al Franken, D-Minn., clearing away any ambiguity over their push to hold the president accountable after the claims of his accusers. About 60 Democratic women in Congress demanded an inquiry into the women's allegations against the president, an unlikely prospect given Republican majorities in the House and Senate.

Gillibrand's Senate colleagues quickly rallied to her side. Among the more forceful was Sen. Mazie Hirono, D-Hawaii, who said on Twitter, "@realDonaldTrump is a misogynist, compulsive liar, and admitted sexual predator. Attacks on Kirsten are the latest example that no one is safe from this bully. He must resign."

The president blamed Democrats for the resurgence of accusations against him from women in the past, saying Tuesday that the "fabricated stories" were a result of Democrats being unable to prove his campaign colluded with the Russians.

He said the "false accusations" came from "women who I don't know and/or have never met."

That claim does not appear to be credible. Trump has met at least five of the more than a dozen women who have accused him of sexual misconduct.