WASHINGTON — President Donald Trump started a Twitter war with Sen. Kirsten Gillibrand on Tuesday, calling her a "lightweight’’ and "flunky’’ to Senate Minority Leader Charles E. Schumer, claiming "she would do anything for’’ campaign contributions.

But Gillibrand shot back on Twitter, calling him unfit for the presidency. And critics suggested the President's "do anything" for a donation remark was an effort to "slut-shame" the New York Democrat.

Trump's tweet came a day after Gillibrand and other Democratic lawmakers called for Trump to resign due to what she termed "credible’’ and "numerous’’ accusations of sexual misconduct dating back to the 1970s. If he does not quit, Gillibrand said, Congress should conduct bipartisan hearings into the allegations.

"You cannot silence me or the millions of women who have gotten off the sidelines to speak out about the unfitness and shame you have brought to the Oval Office,’’ Gillibrand tweeted Tuesday.

Gillibrand allies quickly jumped to her defense. "Are you really trying to bully, intimidate and slut-shame @SenGillibrand? Do you know who you're picking a fight with? Good luck with that, @realDonaldTrump,’’ Sen. Elizabeth Warren, D-Mass., tweeted.

"Slut-shame’’ was a reference to Trump’s suggestive words that Gillibrand "would do anything’’ for campaign donations.

Trump’s entire tweet: "Lightweight Senator Kirsten Gillibrand, a total flunky for Chuck 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. Very disloyal to Bill & Crooked-USED!’’

The charges of sexual assault against Trump gained prominence during the 2016 campaign when an "Access Hollywood" audiotape revealed Trump using vulgar language to describe pursuit of women and groping. But the recent spate of accusations that brought down Hollywood mogul Harvey Weinstein and other powerful men accused of sexual crimes or misconduct have put the spotlight back on Trump’s behavior.

Other Gillibrand backers expressed disgust and amazement that Trump would even suggest Gillibrand would trade or had traded sexual favors for campaign cash.

Former Hillary Clinton campaign official Patti Solis Doyle tweeted: "'And would do anything for them'. What does that mean, @realDonaldTrump?! You, a man, accused by more than a dozen credible women of assault and harassment, has the audacity make this vile, disgusting implication. SHAME!’’

Gillibrand, a senator since 2009, has turned sexual assault in the military and on campus into signature issues. Last week, her statement that Minnesota Democratic Sen. Al Franken should resign amid a growing chorus of sexual-abuse allegations led to numerous other Democrats also calling on the former SNL comedian to quit.

Franken ultimately announced he would vacate his Senate seat.

In recent weeks, Gillibrand also said President Bill Clinton should have resigned over his affair with White House intern Monica Lewinsky.