WASHINGTON – President Trump on Tuesday again denied numerous accusations that he has sexually harassed or assaulted women, claiming that opponents are reviving the allegations because the Russia investigation is failing to show any evidence of collusion.

"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 tweeted in the early morning.

Some of the women who accused Trump during the presidential campaign are now calling for a congressional investigation, amid a sweeping backlash to sexual harassment that started with reports about Hollywood film director Harvey Weinstein and recently resulted in the resignations of lawmakers including Sen. Al Franken, D-Minn., and Rep. Trent Franks, R-Ariz.

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In announcing his resignation last week Franken said it was ironic that he was leaving office while Trump remains in the Oval Office.

Some sitting lawmakers, including Sen. Kirsten Gillibrand, D-N.Y., have called on Trump to resign over the sexual misconduct allegations. Gillibrand has also called for congressional hearings.

In a follow-up tweet on Tuesday, Trump also went after Gillibrand, calling her a "lightweight" senator who would "do anything" for his campaign contributions.

Meanwhile, the Russia probe is only expanding.

Special counsel Robert Mueller and congressional committees continue to investigate connections between Trump's campaign and Russians who tried to influence last year's election by hacking Democratic emails and pushing fake news about Democratic candidate Hillary Clinton. The wide-ranging probe has resulted in four prosecutions against former Trump campaign aides, including its chairman, Paul Manafort.

Earlier this month, Trump's former national security adviser Michael Flynn pleaded guilty to charges of lying to the FBI about his pre-inauguration contacts with the U.S. ambassador to Russia. Flynn, who was forced out of the White House in February after less than a month on the job, also agreed to cooperate with Mueller.

More:President Trump defends Michael Flynn for lying to FBI by claiming Hillary Clinton did the same thing

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While Trump has dismissed the sexual assault misconduct allegations, one high-profile official – United Nations ambassador Nikki Haley – has said his accusers should be heard. "I know that he was elected, but women should always feel comfortable coming forward," Haley said on CBS' Face The Nation on Sunday. "And we should all be willing to listen to them."

White House Press Secretary Sarah Sanders stressed the president's denials.

"The president has addressed these accusations directly and denied all of these allegations," she said. "This took place long before he was elected to be president. And the people of this country, at a decisive election, supported President Trump."

Sanders also said there are “eyewitnesses” who can back the president’s denials, but the White House has never produced any.

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