WASHINGTON — An ex-sister-in-law of Pete Hegseth’s submitted a sworn statement to senators on Tuesday that accused Hegseth, President Donald Trump’s nominee for secretary of defense, of being so “abusive” toward his second wife that she once hid in a closet from him and had a safe word to call for help if she needed to get away from him.

In a Capitol Hill office on Tuesday afternoon, senators were reviewing the affidavit from Danielle Diettrich Hegseth, the former wife of Hegseth’s brother, which describes “erratic and aggressive” behavior by Pete Hegseth that caused his second wife to fear for her safety. According to a copy obtained by The New York Times, it also asserts that he frequently drank to excess both in public and private, including on one occasion she witnessed when he was wearing his military uniform.

The allegations, which Hegseth denied through his lawyer, surfaced as Republicans were working to speed him to confirmation, and could imperil that push. A handful of Republicans who have learned of the accusations in recent days have privately raised serious concerns about them, according to people familiar with the conversations, suggesting that the new information could potentially sap the necessary support for his approval by the Senate.

In her affidavit, reported earlier by NBC News, Danielle Hegseth said she had spoken with the FBI about Pete Hegseth, and had come forward to Congress in the hopes that her account would persuade enough Republicans to block him. She said she was submitting her account at the request of Sen. Jack Reed of Rhode Island, the top Democrat on the Armed Services Committee.

“I have been assured that making this public statement will ensure that certain senators who are still on the fence will vote against Hegseth’s confirmation,” she wrote.

Reed said the account describes behavior that is disqualifying, and “confirms my fears” that the FBI background check on Hegseth had been incomplete.

“The alleged pattern of abuse and misconduct by Mr. Hegseth is disturbing,” he said. “This behavior would disqualify any service member from holding any leadership position in the military, much less being confirmed as the secretary of defense.”

In the affidavit, which was sent Tuesday to the Armed Services panel, Danielle Hegseth wrote that Pete Hegseth’s second wife, Samantha Hegseth, “once hid in her closet from Hegseth because she feared for her personal safety.”

She also said that Samantha Hegseth had given her a code word, shared with Danielle Hegseth and one other person, that she would use if she needed help. According to the sworn statement, Samantha Hegseth texted Danielle Hegseth the code word once in either 2015 or 2016, and Danielle contacted the other person to put the plan into motion.

Danielle Hegseth said that she “did not personally witness physical or sexual abuse by Hegseth,” but that she saw what she described as “erratic and aggressive behavior” by him over many years. She also recounted a number of instances in 2008 or 2009 and around 2013 in which she had witnessed Pete Hegseth being intoxicated to the point of passing out.

The new allegations are strikingly similar to a raft of accusations that had already surfaced since Trump chose him to lead the Pentagon, which Hegseth has adamantly denied and dismissed as politically motivated smears.

Tim Parlatore, a lawyer for Pete Hegseth, denied Danielle Hegseth’s charges.

“Sam has never alleged that there was any abuse, she signed court documents acknowledging that there was no abuse and recently reaffirmed the same during her FBI interview,” Parlatore said, accusing Danielle Hegseth of being “an anti-Trump far-left Democrat” who “had an ax to grind against the entire Hegseth family.”