(CNN) Democratic Sen. Kirsten Gillibrand of New York told CNN on Monday that President Donald Trump should resign over allegations of sexual assault.

"President Trump has committed assault, according to these women, and those are very credible allegations of misconduct and criminal activity, and he should be fully investigated and he should resign," Gillibrand told CNN's Christiane Amanpour in an exclusive interview.

"These allegations are credible; they are numerous, " said Gillibrand, a leading voice in Congress for combating sexual assault in the military. "I've heard these women's testimony, and many of them are heartbreaking."

If he does not "immediately resign," she said, Congress "should have appropriate investigations of his behavior and hold him accountable."

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