Sen. Kirsten Gillibrand (R) (D-NY) speaks as Sen. Bernie Sanders (I-VT) looks on during a news conference at the U.S. Capitol.

Sen. Kirsten Gillibrand on Monday urged President Donald Trump to step down due to numerous sexual misconduct accusations against him.

The New York Democrat told CNN that "President Trump should resign" and if he does not, Congress should start an investigation into the allegations. Her comments come amid a national reckoning over sexual harassment and assault that last week sank her colleague Sen. Al Franken, D-Minn., and two House members.

"These allegations are credible, they are numerous. I've heard these women's testimony, and many of them are heartbreaking," she told CNN.

Gillibrand becomes the fourth Senate Democrat to say Trump should think about stepping down. Sens. Jeff Merkley, D-Ore.; Cory Booker, D-N.J.; and Bernie Sanders, I-Vt., a member of the Senate Democratic caucus, have either said the president should consider resigning or outright urged him to step down.