President Donald Trump dismissed accusations of sexual misconduct on Tuesday, alleging the claims against him were an invention by Democrats who are unable to prove his campaign colluded with Russia to meddle in the 2016 election.

The morning message, delivered on Twitter, amounted to Trump's first direct dismissal as President of the sexual allegations that were renewed this week after originally being levied during last year's presidential campaign.

"Despite thousands of hours wasted and many millions of dollars spent, the Democrats have been unable to show any collusion with Russia - so now they are moving on to the false accusations and fabricated stories of women who I don't know and/or have never met. FAKE NEWS!" Trump wrote on Twitter at 7:10 a.m. ET.

The message combined two topics that have dogged Trump over the course of his first year in office. While the Russia investigation has clouded his administration for months, the charges of sexual misconduct have recently gained new prominence as a wave of similar allegations have led to resignations and firings of powerful men in Congress, Hollywood and the media.

On Monday, some Democratic lawmakers began calling on Trump to resign because of the allegations, including New York Democratic Sen. Kirsten Gillibrand, who said during an interview with CNN's Christiane Amanpour that the women should be believed.

"President Trump should resign," Gillibrand said. "These allegations are credible, they are numerous. I've heard these women's testimony, and many of them are heartbreaking."

Trump responded to those comments a day later, denigrating his home-state senator on Twitter.

"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!" Trump wrote at 8:03 a.m. ET.

Gillibrand responded shortly after, tweeting, "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."

On Monday, three women who accused Trump of sexual harassment or sexual assault detailed their stories anew, claiming Trump visually inspected, groped, fondled or forcibly kissed them during his career as a reality television star and real estate developer.

The women are among the at least 15 who came forward with a wide range of accusations against Trump. The White House rebutted the women on Monday, saying Trump himself had denied the allegations.

"This took place long before he was elected to be president," White House press secretary Sarah Sanders said. "And the people of this country, at a decisive election, supported President Trump, and we feel like these allegations have been answered through that process."

That message ran counter to at least one other member of Trump's administration -- Nikki Haley, the US ambassador to the United Nations -- who said on Sunday that Trump's accusers deserve to be heard.

"I know that he was elected," Haley said on CBS. "But, you know, women should always feel comfortable coming forward. And we should all be willing to listen to them."

The-CNN-Wire

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